Get documents about "week 2 _day 8 to day 14_
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- 10/7/2009
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Document Sample
Week 2: At a Glance
Day 8. Handling Errors
try/catch
try/catch request
Week 2 – Page 1
Syntax Errors
out.prinbln("Hello!") ch03_21.jsp
ch08_01.jsp
<HTML> <HEAD> <TITLE>Passing Arrays to Methods</TITLE> </HEAD> <BODY> <H1>Passing Arrays to Methods</H1> <%! void doubler(int a) { for (int loopIndex = 0; loopIndex < a.length; loopIndex++) { a[loopIndex] *= 2; } } %> <% int array[] = {1, 2, 3, 4, 5}; out.println("Before the call to doubler...<BR>"); for (int loopIndex = 0; loopIndex < array.length; loopIndex++) { out.println("array[" + loopIndex + "] = " + array[loopIndex] + "<BR>"); }
Week 2 – Page 2
doubler(array); out.println("After the call to doubler...<BR>"); for (int loopIndex = 0; loopIndex < array.length; loopIndex++) { out.println("array[" + loopIndex + "] = " + array[loopIndex] + "<BR>"); } %> </BODY> </HTML>
Apache Tomcat/4.0.3 - HTTP Status 500 Internal Server Error
org.apache.jasper.JasperException: Unable to compile class for JSP An error occurred between lines: 8 and 16 in the jsp file: /ch08_01.jsp
Week 2 – Page 3
Generated servlet error: D:\tomcat\jakarta-tomcat4.0.3\work\localhost\ch08\ch08_0005f01$jsp.java:15: Attempt to reference field length in a int. for (int loopIndex = 0; loopIndex < a.length; ^
An error occurred between lines: 8 and 16 in t he jsp file: /ch08_01.jsp Generated servlet error: D:\tomcat\jakarta-tomcat4.0.3\work\localhost\ch08\ch08_0005f01$jsp.java:17: [] can only be applied to arrays. It can't be applied to int. a[loopIndex] *= 2; ^
An error occurred between lines: 18 and 36 in the jsp file: /ch08_01.jsp Generated servlet error: D:\tomcat\jakarta-tomcat4.0.3\work\localhost\ch08\ch08_0005f01$jsp.java:83: Incompatible type for method. Can't convert int[] to int. doubler(array); ^ 3 errors at org.apache.jasper.compiler.Compiler.compile(Compiler.java:285) at org.apache.jasper.servlet.JspServlet.loadJSP(JspServlet.java:552) at org.apache.jasper.servlet.JspServlet$JspServl etWrapper.loadIfNecessary (JspServlet. java:177) at org.apache.jasper.servlet.JspServlet$JspServletWrapper.service (JspServlet.java: 189) at org.apache.jasper.servlet.JspServlet.serviceJspFile (JspServlet.java:382) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:474) at javax.servlet.http.HttpServlet.servic e(HttpServlet.java:853) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter ( ApplicationFilterChain.java:247) at org.apache.catalina.core.ApplicationFilterChain.doFilter (ApplicationFilterChain. java:193) at org.apache.catalina.core.StandardWrapperValve.invoke (StandardWrapperValve.java: 243) at org.apache.catalina.core.StandardPipeline.invokeNext (StandardPipeline.java:566) .
Week 2 – Page 4
. .
org.apache.jasper.JasperException: Unable to compile class for JSP
Incompatible type for method. Can't convert int[] to int
doubler(array);
doubler
int array[] = {1, 2, 3, 4, 5}; . . . doubler(array); doubler
void doubler(int a) { for (int loopIndex = 0; loopIndex < a.length; loopIndex++) { a[loopIndex] *= 2; } } void doubler(int[] a)
javac
Week 2 – Page 5
Runtime Errors
ch08_02.jsp
<HTML> <HEAD> <TITLE>Causing a Runtime Error</TITLE> </HEAD> <BODY> <H1>Causing a Runtime Error</H1> <% int int1 = 1; int1 = int1 / 0; out.println("The answer is " + int1); %> </BODY> </HTML>
Week 2 – Page 6
java.lang.ArithmeticException: / by zero / by zero
/ by zero
Exceptions
Exception Throwable java.lang.Exception java.lang.Throwable
Throwable
getMessage
String
Week 2 – Page 7
java.lang.Throwable
Throwable() Throwable(String message)
Throwable Throwable
String getLocalizedMessage() String getMessage() Throwable void printStackTrace() Throwable
void printStackTrace(PrintStream s) void printStackTrace(PrintWriter s) String toString() Throwable
Exception
Throwable Throwable Throwable
Exception java.lang.Exception
Exception() Exception(String s)
Exception Exception
Exception
try/catch
Using try/catch Blocks
try catch
Week 2 – Page 8
try/catch
try { // Sensitive code } catch (Exception1Type e1) { // Handle exception1 type } catch (Exception1Type e1) { // Handle exception1 type } . . . [finally { // Code to be executed before try block ends }] try catch try/catch finally finally finally finally
catch catch
try/catch catch exception e getMessage try/catch ch08_03.jsp catch exception
<HTML> <HEAD> <TITLE>Using a try/catch Block</TITLE> </HEAD> <BODY> <H1>Using a try/catch Block</H1> <% try{ int int1 = 1; int1 = int1 / 0; out.println("The answer is " + int1); } catch (Exception e){ out.println("An exception occurred: " + e.getMessage()); } %> </BODY>
Week 2 – Page 9
</HTML>
/ by zero
getMessage Exception
Exception toString
out.println
Exception
toString
Week 2 – Page 10
Exception
ch08_04.jsp
<HTML> <HEAD> <TITLE>Using a try/catch Block</TITLE> </HEAD> <BODY> <H1>Using a try/catch Block</H1> <% try{ int int1 = 1; int1 = int1 / 0; out.println("The answer is " + int1); } catch (Exception e){ out.println("An exception occurred: " + e); } %> </BODY> </HTML>
java.lang.ArithmeticException
Handling Specific Exception Types
Week 2 – Page 11
Exception
AclNotFoundException ActivationException AlreadyBoundException ApplicationException ArithmeticException ArrayIndexOutOfBoundsException AWTException BadLocationException ClassNotFoundException CloneNotSupportedException DataFormatException ExpandVetoException FileException GeneralSecurityException IllegalAccessException InstantiationException InterruptedException IntrospectionException InvocationTargetException IOException LastOwnerException NoninvertibleTransformException NoSuchFieldException NoSuchMethodException NotBoundException NotOwnerException ParseException PrinterException PrivilegedActionException PropertyVetoException RemarshalException RuntimeException ServerNotActiveException SQLException TooManyListenersException UnsupportedFlavorException UnsupportedLookAndFeelException UserException Exception catch
Week 2 – Page 12
ArrayIndexOutOfBoundsException
try { . . . } catch (ArrayIndexOutOfBoundsException e) { out.println("Array index out of bounds"); }
array[0]
array[99] array[100] ArrayIndexOutOfBoundsException
ch08_05.jsp
<HTML> <HEAD> <TITLE>Catching an ArrayIndexOutOfBoundsException Exception</TITLE> </HEAD> <BODY> <H1>Catching an ArrayIndexOutOfBoundsException Exception</H1> <% try { int array[] = new int[100]; array[100] = 100; } catch (ArrayIndexOutOfBoundsException e) { out.println("Array index out of bounds."); } %> </BODY> </HTML>
ArrayIndexOutOfBoundsException ArrayIndexOutOfBoundsException
Week 2 – Page 13
Catching Multiple Exceptions
catch catch try/catch
catch Exception
catch
Week 2 – Page 14
ch08_06.jsp
<HTML> <HEAD> <TITLE>Catching an ArrayIndexOutOfBoundsException Exception</TITLE> </HEAD> <BODY> <H1>Catching an ArrayIndexOutOfBoundsException Exception</H1> <% try { int array[] = new int[100]; array[100] = 100; } catch (ArrayIndexOutOfBoundsException e) { out.println("Array index out of bounds."); } catch(ArithmeticException e) { out.println("Arithmetic exception: " + e); } catch(Exception e) { out.println("An error occurred: " + e); } %> </BODY> </HTML> catch try/catch
Nesting try/catch Statements
try try catch catch catch try try try
try/catch
ch08_07.jsp
<HTML> <HEAD> <TITLE>Nesting try/catch Statements</TITLE> </HEAD>
Week 2 – Page 15
<BODY> <H1>Nesting try/catch Statements</H1> <% try { try { int c[] = {0, 1, 2, 3}; c[4] = 4; } catch(ArrayIndexOutOfBoundsException e) { out.println("Array index out of bounds: " + e); } } catch(ArithmeticException e) { out.println("Divide by zero: " + e); } %> </BODY> </HTML>
try/catch
Week 2 – Page 16
Throwing Exceptions Yourself
Exception catch Exception ArithmeticException throw
ch08_08.jsp
<HTML> <HEAD> <TITLE>Throwing an Exception</TITLE> </HEAD> <BODY> <H1>Throwing an Exception</H1> <% try { throw new ArithmeticException("Math Exception!"); } catch(ArithmeticException e) { out.println("Exception message: " + e); } %> </BODY> </HTML>
catch
Throwing Exceptions from Methods
out
Week 2 – Page 17
<HTML> <HEAD> <TITLE>Passing the out Object to a Method</TITLE> </HEAD> <BODY> <H1>Passing the out Object to a Method</H1> <%! void printem(javax.servlet.jsp.JspWriter out) throws java.io.IOException { out.println("Hello from JSP!"); } %> <% printem(out); %> </BODY> </HTML> out printem out java.io.IOException
throws
doWork ArrayIndexOutOfBoundsException
<%! void doWork() throws ArrayIndexOutOfBoundsException { int array[] = new int[100]; array[100] = 100; } %> doWork catch try
<% try {
Week 2 – Page 18
doWork(); } catch (ArrayIndexOutOfBoundsException e) { out.println("Array out of bounds exception"); } %>
ch08_09.jsp
<HTML> <HEAD> <TITLE>Throwing Exceptions From Methods</TITLE> </HEAD> <BODY> <H1>Throwing Exceptions From Methods</H1> <%! void doWork() throws ArrayIndexOutOfBoundsException { int array[] = new int[100]; array[100] = 100; } %> <% try { doWork(); } catch (ArrayIndexOutOfBoundsException e) { out.println("Array out of bounds exception"); } %> </BODY> </HTML>
doWork
Week 2 – Page 19
Creating a Custom Exception Object
Exception
NewException Exception extends
class NewException extends Exception { . . . } NewException Exception getMessage toString out.println toString
Week 2 – Page 20
class NewException extends Exception { int value; public String toString() { return "NewException " + value; } NewException(int v) { value = v; } } doWork NewException
0 doWork
ch08_10.jsp
<HTML> <HEAD> <TITLE>Creating a Custom Exception Object</TITLE> </HEAD> <BODY> <H1>Creating a Custom Exception Object</H1> <%! class NewException extends Exception { int value; public String toString() { return "NewException " + value; } NewException(int v) { value = v; } } void doWork(int value) throws NewException { if(value == 0){ throw new NewException(value); } } %> <% try {
Week 2 – Page 21
doWork(3); doWork(2); doWork(1); doWork(0); } catch (NewException e) { out.println("Exception: " + e); } %> </BODY> </HTML>
Printing to the Server Console
System.out.println out.println System.out.println
Week 2 – Page 22
ch08_11.jsp
<HTML> <HEAD> <TITLE>Printing to the Server Console</TITLE> </HEAD> <BODY> <H1>Printing to the Server Console</H1> <% try{ int value = 1; value = value / 0; } catch (Exception e){ System.out.println(e.getMessage()); } %> </BODY> </HTML>
/ by zero
Week 2 – Page 23
Exception
printStackTrace
ch08_12.jsp
<HTML> <HEAD> <TITLE>Printing a Stack Trace to the Server Console</TITLE> </HEAD> <BODY> <H1>Printing a Stack Trace to the Server Console</H1> <% try{ int value = 1; value = value / 0; } catch (Exception e){ e.printStackTrace(); } %> </BODY> </HTML>
Using Log Files
http://localhost:8080/examples/ server.xml jakarta-tomcat-4.0.3\conf
<!-- Tomcat Examples Context --> <Context path="/examples" docBase="examples" debug="0" reloadable="true" crossContext="true">
Week 2 – Page 24
<Logger className="org.apache.catalina.logger.FileLogger" prefix="localhost_examples_log." suffix=".txt" timestamp="true"/>
localhost_examples_log.2003-03-29.txt
2003-05-10 10:54:22 StandardWrapperValve[jsp]: Servlet.service() for servlet jsp threw exception java.lang.ArithmeticException: / by zero at org.apache.jsp.simple_0005ferror$jsp._jspService(simple_0005ferror$jsp. java:60) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:107) at javax.servlet.http.HttpServlet.service(HttpSe rvlet.java:853) at org.apache.jasper.servlet.JspServlet$JspServletWrapper. service(JspServlet.java: 202) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet. java:382) at org.apache.jasper.servlet.JspServlet.service(JspServlet.ja va:474) at javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter ( ApplicationFilterChain.java:247) at org.apache.catalina.core.ApplicationFilterChain.doFilter (ApplicationFilterChain. java:193) at org.apache.catalina.core.StandardWrapperValve.invoke (StandardWrapperValve.java: 243) at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline. java:566) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline. java:472) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943) at org.apache.catalina.core.StandardContextValve.invoke (StandardContextValve.java: 190) at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline. java:566) at org.apache.catalina.authenticator.AuthenticatorBase.invoke (AuthenticatorBase.
Week 2 – Page 25
java:475) at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline. java:564) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline. java:472) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943) at org.apache.catalina.core.StandardContext.invoke(StandardContext. java:2343) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve. java:180) at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline. java:566) at org.apache.catalina.valves.ErrorDispatcherValve.invoke (ErrorDispatcherValve.java: 170) at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline. java:564) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve. java:170) at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline. java:564) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve. java:468) at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline. java:564) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline. java:472) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943) at org.apache.catalina.core.StandardEngineValve.invoke (StandardEngineValve.java:174) at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline. java:566) at org.apache.catalina.core.StandardPipeline.invoke(Standa rdPipeline. java:472) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943) at org.apache.catalina.connector.http.HttpProcessor.process(HttpProcessor. java:1012) at org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor. java:1107) at java.lang.Thread.run(Thread.java:484)
Week 2 – Page 26
2002-05-10 10:56:13 SessionListener: contextDestroyed() 2002-05-10 10:56:13 ContextListener: contextDestroyed()
Using JSP Error Pages
page errorPage ch08_14.jps ch08_13.jsp
<%@ page errorPage="ch08_14.jsp" %> <HTML> <HEAD> <TITLE>Using an Error Page</TITLE> </HEAD> <BODY> <H1>Using an Error Page</H1> <% int value = 1; value = value / 0; %> </BODY> </HTML>
page "true" "false" ch08_14.jsp
isErrorPage
<%@ page isErrorPage="true" %> <HTML> <HEAD> <TITLE>An Error Page</TITLE> </HEAD> <BODY> <H1>An Error Page</H1> There was an error! Don't Panic!!! <BR> Consult your physician immediately. </BODY> </HTML>
Week 2 – Page 27
ch08_13.jsp
Using JSP Error Pages: The exception Object
request exception java.lang.Throwable ch08_16.jsp exception ch08_15.jsp toString
<%@ page errorPage="ch08_16.jsp" %> <HTML>
Week 2 – Page 28
<HEAD> <TITLE>Using the exception Object</TITLE> </HEAD> <BODY> <H1>Using the exception Object</H1> <% int value = 1; value = value / 0; %> </BODY> </HTML> ch06_16.jsp exception
exception ch08_16.jsp
<%@ page isErrorPage="true" %> <HTML> <HEAD> <TITLE>An Error Page Using the exception Object</TITLE> </HEAD> <BODY> <H1>An Error Page Using the exception Object</H1> An error occurred: <%= exception.toString() %> </BODY> </HTML>
ch08_15.jsp ch08_15.jsp exception
ch08_16.jsp
Week 2 – Page 29
Using JSP Error Pages: request Object Attributes
request String request "message" String setAttribute
request
ch08_17.jsp
<%@ page errorPage="ch08_18.jsp" %> <HTML> <HEAD> <TITLE>Using request Object Attributes</TITLE> </HEAD> <BODY> <H1>Using request Object Attributes</H1> <% request.setAttribute("message", "Divide by zero."); int value = 1;
Week 2 – Page 30
value = value / 0; %> </BODY> </HTML> getAttribute
exception ch08_18.jsp
<%@ page isErrorPage="true" %> <HTML> <HEAD> <TITLE>An Error Page Using Request Attributes</TITLE> </HEAD> <BODY> <H1>An Error Page Using the exception Object</H1> An error occurred: <%= request.getAttribute("message") %> </BODY> </HTML>
request
Week 2 – Page 31
Summary
try/catch try/catch
try/catch catch finally
try
Exception ArrayIndexOutOfBoundsException catch try try/catch throw catch Exception
page exception request
request
Q&A
try/catch
try/catch try/catch
Week 2 – Page 32
Workshop
Quiz
Exception finally Exception out.println request try/catch
Exercises
try/catch
+ - *
/
ArithmeticException
Week 2 – Page 33
Day 9. Using Custom JSP Tags
<% ... %> <jsp:getProperty>
Request
web.xml
Request
request response
<jsp:useBean> <jsp:getProperty> <jsp:setProperty>
Week 2 – Page 34
Tag Libraries
Application Taglib DateTime Taglib Date
Mailer Taglib Page Taglib Random Taglib Regexp Taglib Random Regexp
Request Taglib Response Taglib Session Taglib XSL Taglib
Week 2 – Page 35
Request
The Request Tag Library
Request request request
Request
<req:existsHeader name="User-Agent"> User-Agent=<req:header name="User-Agent"/> </req:existsHeader> <req:existsHeader> Request User-Agent <req:header> <req:header> <req:existsHeader> request
<% if(request.getHeader("User-Agent") != null) { out.println("User-Agent=" + request.getHeader("User-Agent"); } %>
Week 2 – Page 36
Downloading the Request Tag Library
Request
Request Request Taglib
Request jakarta-taglibs-request-1.0.zip 1.0.tar.gz
jakarta-taglibs-request-
Request request.tld /WEB-INF request.jar /WEB-INF/lib request-doc.war
request-examples.war
Installing the Request Tag Library
Request
webapps\ch09 request.tld request.jar Request
webapps\ch09\WEB-INF webapps\ch09\WEB-INF\lib
request-
Week 2 – Page 37
examples.war
C:\directory>jar xvf request-examples.war Request index.html request.jsp web.xml
index.html web.xml
request.jsp webapps\ch09 webapps\ch09\WEB-INF index.html ch09_02.jsp
request.jsp
ch09_01.html
index.html ch09_01.html
Request
Week 2 – Page 38
Request Request
request ch09_01.html
<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso8859-1"> </head> <body bgcolor="#FFFFFF"> <center> <h1> Jakarta REQUEST Taglib Example</h1></center> <br> <p>This page includes a number of hidden input paramters that can then be seen when viewing the request.jsp example page.<br><br> <form action="request.jsp" method="POST"> <input type="hidden" name="test1" value="This is a test"> <input type="hidden" name="test2" value="This is another test"> <input type="hidden" name="test3" value="This is a third test"> <input type="hidden" name="test3" value="Third test with multiple values"> <input type="hidden" name="test4" value="AAbb"> Select the <input type="submit" name="submit" value="SUBMIT"> button to see the output from the request.jsp example page. </form> <br> See the source from the <a href="request.html">request.jsp</a> example page. </body> </html>
request.jar Request
Week 2 – Page 39
Jakarta REQUEST Taglib Example Cookies received with request: Cookie name: Comment: Domain: MaxAge: Path: Secure: Value: Version: JSESSIONID
-1 0 44454937C05623D4121E3B8ED9F36C75 0
Week 2 – Page 40
See if JSESSIONID Cookie exists JSESSIONID=44454937C05623D4121E3B8ED9F36C75 HTTP Headers received with request: accept = image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/msword, application/vnd.ms-excel, application/vnd.ms-powerpoint, */* referer = http://localhost:8080/ch09/ch09_01.html accept-language = en-us content-type = application/x-www-form-urlencoded accept-encoding = gzip, deflate user-agent = Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; COM+ 1.0.2204; .NET CLR 1.0.3512) host = localhost:8080 content-length = 137 connection = Keep-Alive cache-control = no-cache cookie = JSESSIONID=44454937C05623D4121E3B8ED9F36C75 See if User-Agent Header exists User-Agent=Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; COM+ 1.0.2204; .NET CLR 1.0.3512) GET or POST Parameters received with request: test4 = AAbb test3 = This is a third test test2 = This is another test test1 = This is a test submit = SUBMIT GET or POST Parameters received with request for test3: test3 = This is a third test test3 = Third test with multiple values See if test1 parameter exists test1=This is a test See if parameter test4 equals "aabb" Parameter test4 does not equal "aabb". See if test4 equals "aabb", ignoring case test4=AAbb Set an attribute named "myatt" See if myatt attribute exists myatt=AAbb Set an attribute named "myatt2" to the Header User-agent See if myatt equals "aabb" Attribute myatt does not equal "aabb". See if myatt equals "aabb", ignoring case myatt=AAbb
Week 2 – Page 41
Now loop through all the attributes myatt2 = Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; COM+ 1.0.2204; .NET CLR 1.0.3512) myatt = AAbb Now remove the attribute myatt See if myatt attribute exists Attribute myatt does not exist. Request Information: AuthType: ContextPath: /ch09 Method: POST PathInfo: PathTranslated: QueryString: RemoteUser: RequestedSessionId: 44454937C05623D4121E3B8ED9F36C75 RequestURI: /ch09/ch09_02.jsp RequestURL: http://localhost:8080/ch09/ch09_02.jsp ServletPath: /ch09_02.jsp CharacterEncoding: ContentLength: 137 ContentType: application/x-www-form-urlencoded Protocol: HTTP/1.1 RemoteAddr: 127.0.0.1 RemoteHost: 127.0.0.1 Scheme: http ServerName: localhost ServerPort: 8080 IsSecure? Session is not using HTTPS. IsSessionFromCookie? Session is using a cookie. IsSessionFromURL? Session is not using a URL. IsSessionValid? Session is not valid. IsUserInRole "admin"? User is not in role admin. Log a message to the servlet context log. ch09_02.jsp ch09_02.jsp Request lib ch09_02.jsp Request
<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> <head> <title>Jakarta REQUEST Taglib Example</title> </head> <body bgcolor="white"> <center> <h1> Jakarta REQUEST Taglib Example</h1></center> <br>
Week 2 – Page 42
<%@ taglib uri="http://jakarta.apache.org/taglibs/request-1.0" prefix="req" %> <p> <pre> Cookies received with request: <req:cookies id="oatmeal"> Cookie name: Comment: Domain: MaxAge: Path: Secure: Value: Version: </req:cookies> <jsp:getProperty <jsp:getProperty <jsp:getProperty <jsp:getProperty <jsp:getProperty <jsp:getProperty <jsp:getProperty <jsp:getProperty name="oatmeal" name="oatmeal" name="oatmeal" name="oatmeal" name="oatmeal" name="oatmeal" name="oatmeal" name="oatmeal" property="name"/> property="comment"/> property="domain"/> property="maxAge"/> property="path"/> property="secure"/> property="value"/> property="version"/>
See if JSESSIONID Cookie exists <req:existsCookie name="JSESSIONID"> JSESSIONID=<req:cookie name="JSESSIONID"/> </req:existsCookie> <req:existsCookie name="JSESSIONID" value="false"> Cookie JSESSIONID does not exist. </req:existsCookie> HTTP Headers received with request: <req:headers id="hdrs"> <jsp:getProperty name="hdrs" property="name"/> = <jsp:getProperty name="hdrs" property="header"/> </req:headers> See if User-Agent Header exists <req:existsHeader name="User-Agent"> User-Agent=<req:header name="User-Agent"/> </req:existsHeader> <req:existsHeader name="User-Agent" value="false"> Header User-Agent does not exist. </req:existsHeader> GET or POST Parameters received with request: <req:parameters id="param"> <jsp:getProperty name="param" property="name"/> = <jsp:getProperty name="param" property="value"/> </req:parameters> GET or POST Parameters received with request for test3: <req:parameters id="param" name="test3"> <req:parameterValues id="pv"> <jsp:getProperty name="param" property="name"/> = <jsp:getProperty name="pv" property="value"/> </req:parameterValues> </req:parameters>
Week 2 – Page 43
See if test1 parameter exists <req:existsParameter name="test1"> test1=<req:parameter name="test1"/> </req:existsParameter> <req:existsParameter name="test1" value="false"> Parameter test1 does not exist. </req:existsParameter> See if parameter test4 equals "aabb" <req:equalsParameter name="test4" match="aabb"> test4=<req:parameter name="test4"/> </req:equalsParameter> <req:equalsParameter name="test4" match="aabb" value="false"> Parameter test4 does not equal "aabb". </req:equalsParameter> See if test4 equals "aabb", ignoring case <req:equalsParameter name="test4" match="aabb" ignoreCase="true"> test4=<req:parameter name="test4"/> </req:equalsParameter> <req:equalsParameter name="test4" match="aabb" value="false" ignoreCase="true"> Parameter test4 does not equal "aabb", ignoring case. </req:equalsParameter> Set an attribute named "myatt" <req:setAttribute name="myatt">AAbb</req:setAttribute> See if myatt attribute exists <req:existsAttribute name="myatt"> myatt=<req:attribute name="myatt"/> </req:existsAttribute> <req:existsAttribute name="myatt" value="false"> Attribute myatt does not exist. </req:existsAttribute> Set an attribute named "myatt2" to the Header User-agent <req:setAttribute name="myatt2"><req:header name="UserAgent"/></req:setAttribute> See if myatt equals "aabb" <req:equalsAttribute name="myatt" match="aabb"> myatt=<req:attribute name="myatt"/> </req:equalsAttribute> <req:equalsAttribute name="myatt" match="aabb" value="false"> Attribute myatt does not equal "aabb". </req:equalsAttribute> See if myatt equals "aabb", ignoring case <req:equalsAttribute name="myatt" match="aabb" ignoreCase="true"> myatt=<req:attribute name="myatt"/> </req:equalsAttribute> <req:equalsAttribute name="myatt" match="aabb" value="false" ignoreCase="true"> Attribute myatt does not equal "aabb", ignoring case. </req:equalsAttribute> Now loop through all the attributes <req:attributes id="att"> <jsp:getProperty name="att" property="name"/> = <jsp:getProperty
Week 2 – Page 44
name="att" property="attribute"/> </req:attributes> Now remove the attribute myatt <req:removeAttribute name="myatt"/> See if myatt attribute exists <req:existsAttribute name="myatt"> myatt=<req:attribute name="myatt"/> </req:existsAttribute> <req:existsAttribute name="myatt" value="false"> Attribute myatt does not exist. </req:existsAttribute> <req:request id="rq"/> Request Information: AuthType: <jsp:getProperty name="rq" property="authType"/> ContextPath: <jsp:getProperty name="rq" property="contextPath"/> Method: <jsp:getProperty name="rq" property="method"/> PathInfo: <jsp:getProperty name="rq" property="pathInfo"/> PathTranslated: <jsp:getProperty name="rq" property="pathTranslated"/> QueryString: <jsp:getProperty name="rq" property="queryString"/> RemoteUser: <jsp:getProperty name="rq" property="remoteUser"/> RequestedSessionId: <jsp:getProperty name="rq" property="requestedSessionId"/> RequestURI: <jsp:getProperty name="rq" property="requestURI"/> RequestURL: <jsp:getProperty name="rq" property="requestURL"/> ServletPath: <jsp:getProperty name="rq" property="servletPath"/> CharacterEncoding: <jsp:getProperty name="rq" property="characterEncoding"/> ContentLength: <jsp:getProperty name="rq" property="contentLength"/> ContentType: <jsp:getProperty name="rq" property="contentType"/> Protocol: <jsp:getProperty name="rq" property="protocol"/> RemoteAddr: <jsp:getProperty name="rq" property="remoteAddr"/> RemoteHost: <jsp:getProperty name="rq" property="remoteHost"/> Scheme: <jsp:getProperty name="rq" property="scheme"/> ServerName: <jsp:getProperty name="rq" property="serverName"/> ServerPort: <jsp:getProperty name="rq" property="serverPort"/> </pre> <br><br> <p> IsSecure? <req:isSecure>Session is using HTTPS.</req:isSecure> <req:isSecure value="false">Session is not using HTTPS.</req:isSecure> <br><br> <p> IsSessionFromCookie? <req:isSessionFromCookie>Session is using a cookie.</req:isSessionFromCookie> <req:isSessionFromCookie value="false">Session is not using a cookie.</req: isSessionFromCookie> <br><br> <p> IsSessionFromURL? <req:isSessionFromUrl>Session is using a URL.</req:isSessionFromUrl> <req:isSessionFromUrl value="false">Session is not using a URL.</req:isSessionFromUrl>
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<br><br> <p> IsSessionValid? <req:isSessionValid>Session is valid.</req:isSessionValid> <req:isSessionValid value="false">Session is not valid.</req:isSessionValid> <br><br> <p> IsUserInRole "admin"? <req:isUserInRole role="admin">User is in role admin.</req:isUserInRole> <req:isUserInRole role="admin" value="false">User is not in role admin.</req:isUserInRole> <br><br> Log a message to the servlet context log. <req:log> Test of logging to your servlet context log by the request taglib. </req:log> </body> </html>
Using a Tag Library
Request taglib
<%@ taglib uri="http://jakarta.apache.org/taglibs/reques t-1.0" prefix="req" %> taglib
taglib req headers <req:headers id="hdrs"> . . . </req:headers> jsp req Request taglib <jsp:forward> jsp
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HTTP Headers
Request <req:headers> <jsp:getProperty> <req:headers> hdrs name value
HTTP Headers received with request: <req:headers id="hdrs"> <jsp:getProperty name="hdrs" property="name"/> = <jsp:getProperty name="hdrs" property="header"/> </req:headers>
HTTP Headers received with request: accept = image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/msword, application/vnd.ms-excel, application/vnd.ms-powerpoint, */* referer = http://localhost:8080/ch09/ch09_01.html accept-language = en-us content-type = application/x-www-form-urlencoded accept-encoding = gzip, deflate user-agent = Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; COM+ 1.0.2204; .NET CLR 1.0.3512) host = localhost:8080 content-length = 137 connection = Keep-Alive cache-control = no-cache cookie = JSESSIONID=44454937C05623D4121E3B8ED9F36C75 Request <req:headers> User-Agent <req:existsHeader> <req:header>
See if User-Agent Header exists <req:existsHeader name="User-Agent"> User-Agent=<req:header name="User-Agent"/> </req:existsHeader>
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<req:existsHeader name="User-Agent" value="false"> Header User-Agent does not exist. </req:existsHeader>
See if User-Agent Header exists User-Agent=Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; COM+ 1.0.2204; .NET CLR 1.0.3512)
Request Parameters
request
<input type="hidden" <input type="hidden" <input type="hidden" <input type="hidden" values"> <input type="hidden"
name="test1" name="test2" name="test3" name="test3"
value="This is a test"> value="This is another test"> value="This is a third test"> value="Third test with multiple
name="test4" value="AAbb"> <req:parameters> <req:headers>
GET or POST Parameters received with request: <req:parameters id="param"> <jsp:getProperty name="param" property="name"/> = <jsp:getProperty name="param" property="value"/> </req:parameters> test3 <req:parameterValues> <jsp:getProperty>
GET or POST Parameters received with request for test3: <req:parameters id="param" name="test3"> <req:parameterValues id="pv"> <jsp:getProperty name="param" property="name"/> = <jsp:getProperty name="pv"
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property="value"/> </req:parameterValues> </req:parameters>
<req:parameter> <req:existsParameter>
See if test1 parameter exists <req:existsParameter name="test1"> test1=<req:parameter name="test1"/> </req:existsParameter> <req:existsParameter name="test1" value="false"> Parameter test1 does not exist. </req:existsParameter> See if parameter test4 equals "aabb" <req:equalsParameter name="test4" match="aabb"> test4=<req:parameter name="test4"/> </req:equalsParameter> <req:equalsParameter name="test4" match="aabb" value="false"> Parameter test4 does not equal "aabb". </req:equalsParameter> See if test4 equals "aabb", ignoring case <req:equalsParameter name="test4" match="aabb" ignoreCase="true"> test4=<req:parameter name="test4"/> </req:equalsParameter> <req:equalsParameter name="test4" match="aabb" value="false" ignoreCase="true"> Parameter test4 does not equal "aabb", ignoring case. </req:equalsParameter>
GET or POST Parameters received with request: test4 = AAbb test3 = This is a third test test2 = This is another test test1 = This is a test submit = SUBMIT GET or POST Parameters received with request for test3: test3 = This is a third test test3 = Third test with multiple values See if test1 parameter exists test1=This is a test See if parameter test4 equals "aabb" Parameter test4 does not equal "aabb". See if test4 equals "aabb", ignoring case
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test4=AAbb <req:parameter> getParameter getParameter
<req:parameters>
Setting Attributes
Request <req:setAttribute> <req:existsAttribute> <req:attribute> myatt2 request
myatt
Set an attribute named "myatt" <req:setAttribute name="myatt">AAbb</req:setAttribute> See if myatt attribute exists <req:existsAttribute name="myatt"> myatt=<req:attribute name="myatt"/> </req:existsAttribute> <req:existsAttribute name="myatt" value="false"> Attribute myatt does not exist. </req:existsAttribute> Set an attribute named "myatt2" to the Header User-agent <req:setAttribute name="myatt2"> <req:header name="UserAgent"/></req:setAttribute> See if myatt equals "aabb" <req:equalsAttribute name="myatt" match="aabb"> myatt=<req:attribute name="myatt"/> </req:equalsAttribute> <req:equalsAttribute name="myatt" match="aabb" value="false"> Attribute myatt does not equal "aabb". </req:equalsAttribute> See if myatt equals "aabb", ignoring case <req:equalsAttribute name="myatt" match="aabb" ignoreCase="true"> myatt=<req:attribute name="myatt"/> </req:equalsAttribute> <req:equalsAttribute name="myatt" match="aabb" value="false" ignoreCase="true"> Attribute myatt does not equal "aabb", ignoring case. </req:equalsAttribute> Now loop through all the attributes <req:attributes id="att"> <jsp:getProperty name="att" property="name"/> = <jsp:getProperty name="att" property="attribute"/> </req:attributes> Now remove the attribute myatt <req:removeAttribute name="myatt"/>
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See if myatt attribute exists <req:existsAttribute name="myatt"> myatt=<req:attribute name="myatt"/> </req:existsAttribute> <req:existsAttribute name="myatt" value="false"> Attribute myatt does not exist. </req:existsAttribute>
Set an attribute named "myatt" See if myatt attribute exists myatt=AAbb Set an attribute named "myatt2" to the Header User-agent See if myatt equals "aabb" Attribute myatt does not equal "aabb". See if myatt equals "aabb", ignoring case myatt=AAbb Now loop through all the attributes myatt2 = Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; COM+ 1.0.2204; .NET CLR 1. 0.3512) myatt = AAbb Now remove the attribute myatt See if myatt attribute exists Attribute myatt does not exist.
Request Properties
Request getRemoteUser <req:request> <jsp:getProperty> request getMethod ID <req:request>
<req:request id="rq"/> Request Information: AuthType: <jsp:getProperty name="rq" property="authType"/> ContextPath: <jsp:getProperty name="rq" property="contextPath"/> Method: <jsp:getProperty name="rq" property="method"/> PathInfo: <jsp:getProperty name="rq" property="pathInfo"/> PathTranslated: <jsp:getProperty name="rq" property="pathTranslated"/> QueryString: <jsp:getProperty name="rq" property="queryString"/> RemoteUser: <jsp:getProperty name="rq" property="remoteUser"/> RequestedSessionId: <jsp:getProperty name="rq"
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property="requestedSessionId"/> RequestURI: <jsp:getProperty name="rq" property="requestURI"/> RequestURL: <jsp:getProperty name="rq" property="requestURL"/> ServletPath: <jsp:getProperty name="rq" property="servletPath"/> CharacterEncoding: <jsp:getProperty name="rq" property="characterEncoding"/> ContentLength: <jsp:getProperty name="rq" property="contentLength"/> ContentType: <jsp:getProperty name="rq" property="contentType"/> Protocol: <jsp:getProperty name="rq" property="protocol"/> RemoteAddr: <jsp:getProperty name="rq" property="remoteAddr"/> RemoteHost: <jsp:getProperty name="rq" property="remoteHost"/> Scheme: <jsp:getProperty name="rq" property="scheme"/> ServerName: <jsp:getProperty name="rq" property="serverName"/> ServerPort: <jsp:getProperty name="rq" property="serverPort"/>
Request Information: AuthType: ContextPath: /ch09 Method: POST PathInfo: PathTranslated: QueryString: RemoteUser: RequestedSessionId: 44454937C05623D4121E3B8ED9F36C75 RequestURI: /ch09/ch09_02.jsp RequestURL: http://localhost:8080/ch09/ch09_02.jsp ServletPath: /ch09_02.jsp CharacterEncoding: ContentLength: 137 ContentType: application/x-www-form-urlencoded Protocol: HTTP/1.1 RemoteAddr: 127.0.0.1 RemoteHost: 127.0.0.1 Scheme: http ServerName: localhost ServerPort: 8080
<req:parameter> <req:parameters>
<req:xxxx>
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Tag Library Descriptor Files
Request req taglib
<%@ taglib uri="http://jakarta.apache.org/taglibs/reques t-1.0" prefix="req" %> web.xml web.xml request.tld <taglib> WEB-INF
<taglib> <taglib-uri>http://jakarta.apache.org/taglibs/request-1.0</tagliburi> <taglib-location>/WEB-INF/request.tld</taglib-location> </taglib> <taglib-uri> <taglib-location>
request.tld
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.1//EN" "http://java.sun.com/j2ee/dtds/web-jsptaglibrary_1_1.dtd"> <taglib> <tlibversion>1.0</tlibversion> <jspversion>1.1</jspversion> <shortname>request</shortname> <uri>http://jakarta.apache.org/taglibs/request-1.0</uri> <info>The REQUEST custom tag library contains tags which can be used to access all the information about the HTTP request for a JSP page. Tags are provided to access information in the HTTP request for HTTP input parameters from a POST or GET, HTTP Headers, Cookies, request attributes, and session information related to this request.</info> <tag> <name>log</name> <tagclass>org.apache.taglibs.request.LogTag</tagclass>
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<bodycontent>JSP</bodycontent> </tag> . . . <tag> <name>existsQueryString</name> <tagclass>org.apache.taglibs.request.ExistsQueryStringTag</tagclass> <bodycontent>JSP</bodycontent> <attribute> <name>name</name> <required>yes</required> <rtexprvalue>no</rtexprvalue> </attribute> <attribute> <name>value</name> <required>no</required> <rtexprvalue>no</rtexprvalue> </attribute> </tag> </taglib>
<tlib-version> <jspversion> version> <tagclass> <tag-class>
<tlibversion> <jsprequest.tld
<tag> <req:existsQueryString> <name>
<name> <tagclass>
<req:existsQueryString> org.apache.taglibs.request.ExistsQueryStringTa g request.jar ExistsQueryStringTag org.apache.taglibs.request lib org.apache.taglibs.request.ExistsQueryStringTag request.jar
name <attribute>
value
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Creating a Simple Tag
Hello! taglib "l"
log
<%@ taglib uri="http://starpowder.com/taglibs" prefix="l"%> <l:log>
<l:log> I'm sending some text to the server console! </l:log> I'm sending some text to the server console!
ch09_03.jsp
<%@ taglib uri="http://starpowder.com/taglibs" prefix="l"%> <HTML> <HEAD> <TITLE>Creating a Simple Custom Tag</TITLE> </HEAD> <BODY> <H1>Creating a Simple Custom Tag</H1> <l:log>
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I'm sending some text to the server console! </l:log> </BODY> </HTML> http://starpowder.com/taglibs <taglib> web.xml web.xml Request <taglib>
web.xml
ch09\WEB-INF
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN" "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd"> <web-app> <description> Example web application illustrating the use of tags in the "request" custom tag library, from the JAKARTA-TAGLIBS project. </description> <mime-mapping> <extension>txt</extension> <mime-type>text/plain</mime-type> </mime-mapping> . . . <taglib> <taglib-uri> http://jakarta.apache.org/tomcat/examples-taglib </taglib-uri> <taglib-location> /WEB-INF/example-taglib.tld </taglib-location> </taglib> <taglib> <taglib-uri>http://starpowder.com/taglibs</taglib-uri> <taglib-location>/WEB-INF/ch09_04.tld</taglib-location> </taglib> . . .
ch09_04.tld
Creating the Tag Descriptor Library File
ch09_04.tld <l:log> <!DOCTYPE> <!DOCTYPE>
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<?xml version="1.0" encoding="ISO-8859-1" ?> <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.tld"> <?xml version="1.0" encoding="ISO-8859-1" ?>
<taglib>
<?xml version="1.0" encoding="ISO-8859-1" ?> <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.tld"> <taglib> . . . </taglib> <tlib-version> <jsp-version> <short<uri> <description>
name>
<taglib> <tlib-version>1.0</tlib-version> <jsp-version>1.2</jsp-version> <short-name>ch09_05</short-name> <uri>http://starpowder.com/taglibs</uri> <description> A simple tag </description> . . . </taglib> <l:log> <name> <body-content> <description> <tag> <tag-class>
<taglib> <tlib-version>1.0</tlib-version> <jsp-version>1.2</jsp-version>
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<short-name>ch09_05</short-name> <uri>http://starpowder.com/taglibs</uri> <description> A simple tag </description> <!-- log tag --> <tag> <name>log</name> <tag-class>taglib.ch09_05</tag-class> <body-content>TAGDEPENDENT</body-content> <description> Log a message. </description> </tag> </taglib> ch09_04.tld ch09_04.tld
<?xml version="1.0" encoding="ISO-8859-1" ?> <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.tld"> <taglib> <tlib-version>1.0</tlib-version> <jsp-version>1.2</jsp-version> <short-name>ch09_05</short-name> <uri>http://starpowder.com/taglibs</uri> <description> A simple tag </description> <!-- log tag --> <tag> <name>log</name> <tag-class>taglib.ch09_05</tag-class> <body-content>TAGDEPENDENT</body-content> <description> Log a message. </description> </tag> </taglib> <l:log> ch09_05.class
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Creating the Java Support
ch09_05.java
taglib
package taglib; import javax.servlet.jsp.*; import javax.servlet.jsp.tagext.*; import java.io.IOException; . . . ch09_05 extends TagSupport TagSupport doStartTag TagSupport <l:log>
EVAL_BODY_INCLUDE
package taglib; import javax.servlet.jsp.*; import javax.servlet.jsp.tagext.*; import java.io.IOException; public class ch09_05 extends TagSupport { public int doStartTag() throws JspException { return EVAL_BODY_INCLUDE; } . . . } doAfterBody <l:log> Hello! ch09_05.java
package taglib; import javax.servlet.jsp.*;
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import javax.servlet.jsp.tagext.*; import java.io.IOException; public class ch09_05 extends TagSupport { public int doStartTag() throws JspException { return EVAL_BODY_INCLUDE; } public int doAfterBody() throws JspException { System.out.println("Hello!"); return SKIP_BODY; } } servlet.jar jakarta-tomcat-4.0.3\common\lib CLASSPATH CLASSPATH servlet.jar servlet.jar servlet.jar
C:\>SET CLASSPATH=C:\tomcat\jakarta-tomcat-4.0.3\common\lib\servlet.jar ch09_05.java ch09_05.class javac taglib
ch09_05.class
webapps\ch09\WEB-INF\classes\taglib http://localhost:8080/ch09/ch09_03.js p
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ch09_03.jsp Hello!
<l:log>
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Summary
web.xml .class .jar taglib
Request request taglib <taglib> web.xml
TagSupport
Q&A
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Workshop
Quiz
<taglib>
<taglib>
Exercises
Request
Request
Week 2 – Page 63
Day 10. Creating Custom Tags
pageContext
pageContext
A Simple Text-Inserting Tag
<ch10:message>
<ch10:message /> ch10_01.jsp
<%@ taglib prefix="ch10" uri="WEB-INF/ch10_02.tld" %> <HTML>
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<HEAD> <TITLE>A Simple Tag That Inserts Text</TITLE> </HEAD> <BODY> <H1>A Simple Tag That Inserts Text</H1> <ch10:message /> </BODY> </HTML>
web.xml
<taglib>
WEB-INF
taglib
uri
<%@ taglib prefix="ch10" uri="WEB-INF/ch10_02.tld" %> <ch10:message> ch10_02.tld
Creating a TLD File
<ch10:message> ch10_02.tld <!DOCTYPE>
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd"> <taglib> . . . </taglib> <taglib>
<taglib>
<tlib-version> <jsp-version>
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<short-name> <uri> <display-name> <small-icon> <large-icon> <description> <listener> <tag> <taglib> <ch10:message>
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd"> <taglib> <tlib-version>1.0</tlib-version> <jsp-version>1.2</jsp-version> <short-name>TagExamples</short-name> <description>Example tags.</description> <tag> . . . </tag> </taglib> <tag> <tag> <name> <tag-class> <tag>
<name> <tag-class> <tei-class> javax.servlet.jsp.tagext.TagExtraInfo <bodycontent> <displayname>
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<small-icon> <large-icon> <description> <variable> <attribute> ch10_02.tld message ch10_02.tld taglib.ch10_03
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd"> <taglib> <tlib-version>1.0</tlib-version> <jsp-version>1.2</jsp-version> <short-name>TagExamples</short-name> <description>Example tags.</description> <tag> <name>message</name> <tag-class>taglib.ch10_03</tag-class> </tag> </taglib> taglib.ch10_03
Creating the Java Support
taglib.ch10_03 ch10_03.java taglib
package taglib; . . . ch10_03 extends TagSupport
package taglib; import javax.servlet.jsp.tagext.*; import javax.servlet.jsp.*;
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public class ch10_03 extends TagSupport { . . . } TagSupport
TagSupport
java.lang.String id PageContext pageContext PageContext TagSupport
TagSupport() int doAfterBody() int doEndTag() EVAL_PAGE int doStartTag() SKIP_BODY java.lang.String getId() Tag getParent() java.lang.Object getValue (java.lang.String k) java.util.Enumeration getValues() void removeValue(java.lang.String k) void setId(java.lang.String id) void setPageContext (PageContext pageContext) void setParent(Tag t) void setValue(java.lang.String k java.lang.Object o) String id
id
PageContext
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TagSupport javax.servlet.jsp.tagext.IterationTag javax.servlet.jsp.tagext.Tag
javax.servlet.jsp.tagext.IterationTag int EVAL_BODY_AGAIN
int doAfterBody()
javax.servlet.jsp.tagext.Tag
javax.servlet.jsp.tagext.Tag
int EVAL_BODY_INCLUDE int EVAL_PAGE int SKIP_BODY t SKIP_PAGE javax.servlet.jsp.tagext.Tag
int doEndTag() int doStartTag() Tag getParent() void setPageContext(PageContext°pc) void setParent(Tag°t) <ch10:message> </ch10:message> TagSupport doEndTag
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package taglib; import javax.servlet.jsp.tagext.*; import javax.servlet.jsp.*; public class ch10_03 extends TagSupport { public int doEndTag() { . . . } "Hello from JSP!" out.println TagSupport pageContext
Working with the Page Context
out pageContext PageContext exception
pageContext
PageContext
java.lang.String APPLICATION int APPLICATION_SCOPE java.lang.String CONFIG java.lang.String EXCEPTION java.lang.String OUT java.lang.String PAGE int PAGE_SCOPE java.lang.String PAGECONTEXT java.lang.String REQUEST int REQUEST_SCOPE
ServletContext
JspWriter
PageContext ServletRequest
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java.lang.String RESPONSE java.lang.String SESSION int SESSION_SCOPE
ServletResponse PageContext HttpSession PageContext
javax.servlet.jsp.tagext.Tag
java.lang.Object findAttribute (java.lang.String name)
null void forward(java.lang.String relativeUrlPath) ServletRequest ServletResponse
java.lang.Object getAttribute (java.lang.String name) null java.lang.Object getAttribute (java.lang.String name, int scope) null java.util.Enumeration getAttributeNamesInScope (int scope) int getAttributesScope(java.lang.String name) java.lang.Exception getException() exception JspWriter getOut() out JspWriter page Servlet ServletRequest getRequest() request ServletRequest response ServletResponse
java.lang.Object getPage()
ServletResponse getResponse()
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ServletConfig getServletConfig()
ServletConfig
ServletContext getServletContext() HttpSession getSession()
ServletContext session HttpSession
void handlePageException(java.lang.Exception e) void handlePageException(java.lang.Throwable t) handlePageException (Exception) Throwable
void include(java.lang.String relativeUrlPath) ServletRequest ServletResponse void initialize(Servlet servlet, ServletRequest request, ServletResponse response, java.lang.String errorPageURL, boolean needsSession, int bufferSize, and boolean autoFlush) void release() PageContext void removeAttribute(java.lang.String name)
PageContext
void removeAttribute(java.lang.String name, int scope)
void setAttribute(java.lang.String name java.lang.Object attribute) void setAttribute(java.lang.String name java.lang.Object o, int scope)
pageContext out print println EVAL_PAGE
getOut
package taglib;
Week 2 – Page 72
import javax.servlet.jsp.tagext.*; import javax.servlet.jsp.*; public class ch10_03 extends TagSupport { public int doEndTag() throws JspException { try { pageContext.getOut().print("Hello from JSP!"); . . . } return EVAL_PAGE; } } out
ch10_03.java
package taglib; import javax.servlet.jsp.tagext.*; import javax.servlet.jsp.*; public class ch10_03 extends TagSupport { public int doEndTag() throws JspException { try { pageContext.getOut().print("Hello from JSP!"); } catch (Exception e) { throw new JspException(e.toString()); } return EVAL_PAGE; } } ch10_01.jsp
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Creating and Supporting Attributes in Custom Tags
<ch10:message> text
The text is: <ch10:message text="Hello there!"/>
<attribute> <name>
Week 2 – Page 74
<attribute>
<name> <required> true false yes <rtexprvalue> true false yes <description> <type> java.lang.String String no no
<ch10:message>
ch10_04.jsp
<%@ taglib prefix="ch10" uri="WEB-INF/ch10_05.tld" %> <HTML> <HEAD> <TITLE>Supporting Attributes in Custom Tags</TITLE> </HEAD> <BODY> <H1>Supporting Attributes in Custom Tags</H1> The text is: <ch10:message text="Hello there!"/> </BODY> </HTML> text <attribute> java.lang.String <ch10:message>
ch10_05.tld
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd"> <taglib> <tlib-version>1.0</tlib-version> <jsp-version>1.2</jsp-version> <short-name>TagExamples</short-name> <description>Example tags.</description> <tag> <name>message</name>
Week 2 – Page 75
<tag-class>taglib.ch10_06</tag-class> <attribute> <name>text</name> <type>java.lang.String</type> </attribute> </tag> </taglib> <ch10:message> set String text setText
public class ch10_06 extends TagSupport { String text; public void setText(String s) { text = s; } public int doEndTag() throws JspException { try { . . . } return EVAL_PAGE; } } setText text pageContext.getOut().print ch10_06.java text
package taglib; import javax.servlet.jsp.tagext.*; import javax.servlet.jsp.*; public class ch10_06 extends TagSupport { String text; public void setText(String s) { text = s; }
Week 2 – Page 76
public int doEndTag() throws JspException { try { pageContext.getOut().print(text); } catch (Exception e) { throw new JspException(e.toString()); } return EVAL_PAGE; } }
Iterating Tags
Week 2 – Page 77
Cast Cast Cast Cast
member: member: member: member:
Ralph Alice Ed Trixie
<ch10:iterator>
<ch10:iterator> Cast member: </ch10:iterator>
pageContext
names setAttribute <ch10:iterator>
ch10_07.jsp
<%@ taglib prefix="ch10" uri="WEB-INF/ch10_08.tld" %> <HTML> <HEAD> <TITLE>Supporting Iterating Custom Tags</TITLE> </HEAD> <BODY> <H1>Supporting Iterating Custom Tags</H1> <% String[] names = new String[]{ "Ralph", "Alice", "Ed", "Trixie" }; pageContext.setAttribute("names", names); %> <ch10:iterator> Cast member: </ch10:iterator> </BODY> </HTML> <ch10:iterator>
Week 2 – Page 78
ch10_08.tld
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd"> <taglib> <tlib-version>1.0</tlib-version> <jsp-version>1.2</jsp-version> <short-name>TagExamples</short-name> <description>Example tags.</description> <tag> <name>message</name> <tag-class>taglib.ch10_06</tag-class> <attribute> <name>text</name> <type>javalang.String</type> </attribute> </tag> <tag> <name>iterator</name> <tag-class>taglib.ch10_09</tag-class> </tag> </taglib> pageContext getAttribute doStartTag
package taglib; import javax.servlet.jsp.*; import javax.servlet.jsp.tagext.*; public class ch10_09 extends TagSupport { private String[] names = null; public int doStartTag() { names = (String[]) pageContext.getAttribute("names"); return EVAL_BODY_INCLUDE; } . . .
TagSupport IterationTag TagSupport
Week 2 – Page 79
IterationTag
IterationTag
doAfterBody "Cast member:"
IterationTag doAfterBody
EVAL_BODY_AGAIN SKIP_BODY
counter doAfterBody
public class ch10_09 extends TagSupport { private int counter = 0; private String[] names = null; . . . public int doAfterBody() throws JspException { try{ pageContext.getOut().print(" " + names[counter] + "<BR>"); } catch(Exception e){ throw new JspException(e.toString()); } counter++; if(counter >= names.length) { return SKIP_BODY; } return EVAL_BODY_AGAIN; } } } }
Week 2 – Page 80
ch10_09.html
package taglib; import javax.servlet.jsp.*; import javax.servlet.jsp.tagext.*; public class ch10_09 extends TagSupport { private int counter = 0; private String[] names = null; public int doStartTag() { names = (String[]) pageContext.getAttribute("names"); return EVAL_BODY_INCLUDE; } public int doAfterBody() throws JspException { try{ pageContext.getOut().print(" " + names[counter] + "<BR>"); } catch(Exception e){ throw new JspException(e.toString()); } counter++; if(counter >= names.length) { return SKIP_BODY; } return EVAL_BODY_AGAIN; } }
names
Week 2 – Page 81
pageContext
Cooperating Tags
pageContext names
<% String[] names = new String[]{ "Ralph", "Alice", "Ed", "Trixie" }; pageContext.setAttribute("names", names); %> pageContext <ch10:createCast> names names <ch10:createCast>
<ch10:iterator> <ch10:createCast>
Week 2 – Page 82
<ch10:iterator> ch10_10.jsp
<%@ taglib prefix="ch10" uri="WEB-INF/ch10_11.tld" %> <HTML> <HEAD> <TITLE>Supporting Cooperating Custom Tags</TITLE> </HEAD> <BODY> <H1>Supporting Cooperating Custom Tags</H1> <ch10:createCast/> <ch10:iterator> Cast member: </ch10:iterator> </BODY> </HTML>
ch10_11.tld
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd"> <taglib> <tlib-version>1.0</tlib-version> <jsp-version>1.2</jsp-version> <short-name>TagExamples</short-name> <description>Example tags.</description> <tag> <name>message</name> <tag-class>taglib.ch10_06</tag-class> <attribute> <name>text</name> <type>javalang.String</type> </attribute> </tag> <tag> <name>iterator</name> <tag-class>taglib.ch10_09</tag-class> </tag> <tag> <name>createCast</name> <tag-class>taglib.ch10_12</tag-class> </tag> </taglib> <ch10:createCast> <ch10:iterator>
names
Week 2 – Page 83
ch10_12.java
package taglib; import javax.servlet.jsp.tagext.*; public class ch10_12 extends TagSupport { public int doStartTag() { String[] names = new String[] {"Ralph", "Alice", "Ed", "Trixie"}; pageContext.setAttribute("names", names); return SKIP_BODY; } }
Week 2 – Page 84
Using Scripting Variables
pageContext names
<% String[] names = new String[]{ "Ralph", "Alice", "Ed", "Trixie" }; pageContext.setAttribute("names", names); %> <ch10:iterator> Cast member: </ch10:iterator>
<ch10:createCast/>
names
names
PageContext
ch10_13.jsp
<%@ taglib prefix="ch10" uri="WEB-INF/ch10_11.tld" %> <HTML> <HEAD> <TITLE>Using the pageContext Object</TITLE> </HEAD> <BODY> <H1>Using the pageContext Object</H1> <ch10:createCast/> <% String[] names = (String [])pageContext.getAttribute("names"); %> <% for(int loopIndex = 0; loopIndex < names.length; loopIndex++) { out.println("Cast member: " + names[loopInd ex] + "<BR>"); } %> </BODY> </HTML>
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names names
<% String[] names = (String [])pageContext.getAttribute("names"); %>
pageContext
<variable> <variable> <name-given> <name-from-attribute>
<variable>
<name-given>
Week 2 – Page 86
<name-fromattribute> <variable-class> java.lang.String <declare> true <scope> NESTED <scope> false
<variable>
NESTED AT_BEGIN AT_END
doInitBody doAfterBody doStartTag doInitBody doAfterBody doEndTag doStartTag doEndTag names pageContext
names <ch10:createCast> <ch10:createCast /> getAttribute
names
ch10_14.jsp
<%@ taglib prefix="ch10" uri="WEB-INF/ch10_15.tld" %> <HTML> <HEAD> <TITLE>Using Scripting Variables</TITLE> </HEAD> <BODY> <H1>Using Scripting Variables</H1> <ch10:createCast/> <% for(int loopIndex = 0; loopIndex < names.length; loopIndex++) {
Week 2 – Page 87
out.println("Cast member: " + names[loopIndex] + "<BR>"); } %> </BODY> </HTML> names
ch10_15.tld
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd"> <taglib> <tlib-version>1.0</tlib-version> <jsp-version>1.2</jsp-version> <short-name>TagExamples</short-name> <description>Example tags.</description> <tag> <name>message</name> <tag-class>taglib.ch10_06</tag-class> <attribute> <name>text</name> <type>javalang.String</type> </attribute> </tag> <tag> <name>iterator</name> <tag-class>taglib.ch10_09</tag-class> </tag> <tag> <name>createCast</name> <tag-class>taglib.ch10_12</tag-class> <variable> <name-given>names</name-given> <variable-class>java.lang.String []</variable-class> <declare>true</declare> <scope>AT_END</scope> </variable> </tag> </taglib> names <ch10:createCast> names
Week 2 – Page 88
BodyTag
Summary
TagSupport
TagSupport doStartTag SKIP_BODY
EVAL_BODY_INCLUDE
<attribute>
set doAfterBody
Week 2 – Page 89
EVAL_BODY_AGAIN
SKIP_BODY
Q&A
.class
web.xml web.xml web.xml web.xml
Workshop
Quiz
<taglib> <tag> TagSupport
Week 2 – Page 90
String <attribute>
Exercises
<attribute> <required> text <required>true</required> <ch10:message>
<ch10:message> <LI> <ch10:iterator> <UL>
Day 11. Creating More Powerful JavaBeans
Week 2 – Page 91
<jsp:plugin>
Why Inheritance?
TagSupport
TagSupport
Using Inheritance
vehicle start "Starting...<BR>"
class vehicle { public void start()
Week 2 – Page 92
{ out.println("Starting...<BR>"); } } vehicle automobile automobile vehicle extends
class automobile extends vehicle { . . . } automobile start drive automobile vehicle vehicle
automobile
class automobile extends vehicle { public void drive() { out.println("Driving...<BR>"); } } start automobile ch11_01.jsp drive
<HTML> <HEAD> <TITLE>Using Inheritance</TITLE> </HEAD> <BODY> <H1>Using Inheritance</H1> <%! javax.servlet.jsp.JspWriter localOut; class vehicle { public void start() throws java.io.IOException { localOut.println("Starting...<BR>"); }
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} class automobile extends vehicle { public void drive() throws java.io.IOException { localOut.println("Driving...<BR>"); } } %> <% localOut = out; out.println("Creating an automobile...<BR>"); automobile a = new automobile(); a.start(); a.drive(); %> </BODY> </HTML> start automobile drive
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vehicle
automobile
class vehicle { public void start() throws java.io.IOException { System.out.println("Starting...<BR>"); } } class automobile extends vehicle { public void drive() throws java.io.IOException { System.out.println("Driving...<BR>"); } } public class application { automobile a = new automobile(); a.drive(); . . .
.java public
vehicle
.java vehicle.java
public class vehicle { public void start() throws java.io.IOException { System.out.println("Starting...<BR>"); } } vehicle.java vehicle vehicle.class javac .java
Week 2 – Page 95
import
import vehicle; class automobile extends vehicle { public void drive() throws java.io.IOException { System.out.println("Driving...<BR>"); } } public class application { automobile a = new automobile(); a.drive(); . . .
vehicle.class CLASSPATH SET CLASSPATH=c:\classes
C:\classes vehicle.class
Using Access Specifiers
start public drive
access class classname [extends ...] [implements ...] { [access] [static] type variable1; . .
Week 2 – Page 96
. [access] [static] type variableN; [access] [static] type method1 (parameter_list) { . . . } . . . [access] [static] type methodN (parameter_list) { . . . } } access protected private protected public private public
start
private
vehicle
class vehicle { private void start() {
throws java.io.IOException
Week 2 – Page 97
localOut.println("Starting...<BR>"); } } . . . out.println("Creating an automobile...<BR>"); automobile a = new automobile(); a.start(); // This won't work! a.drive(); private start protected
ch11_02.jsp
<HTML> <HEAD> <TITLE>Using Restricted Access</TITLE> </HEAD> <BODY> <H1>Using Restricted Access</H1> <%! javax.servlet.jsp.JspWriter localOut; class vehicle { protected void start() throws java.io.IOException { localOut.println("Starting...<BR>"); } } class automobile extends vehicle { public void drive() throws java.io.IOException { localOut.println("Driving...<BR>"); } } %> <% localOut = out; out.println("Creating an automobile...<BR>"); automobile a = new automobile(); a.start(); a.drive(); %>
Week 2 – Page 98
</BODY> </HTML> protected
Calling Superclass Constructors
int a void
Week 2 – Page 99
class a { a() { out.println("In a\'s constructor...<BR>"); } } b a
class b extends a { } b a
b newObject = new b();
b
ch11_03.jsp
<HTML> <HEAD> <TITLE>Calling Superclass Constructors</TITLE> </HEAD> <BODY> <H1>Calling Superclass Constructors</H1> <%! javax.servlet.jsp.JspWriter localOut; class a { a() throws java.io.IOException { localOut.println("In a\'s constructor...<BR>"); } } class b extends a { b() throws java.io.IOException {
Week 2 – Page 100
localOut.println("In b\'s constructor...<BR>"); } } %> <% localOut = out; b obj = new b(); %> </BODY> </HTML>
b
a
b
b
ch11_04.jsp
<HTML> <HEAD> <TITLE>Using Parameterized Constructors</TITLE>
Week 2 – Page 101
</HEAD> <BODY> <H1>Using Parameterized Constructors</H1> <%! javax.servlet.jsp.JspWriter localOut; class a { a() throws java.io.IOException { localOut.println("In a\'s constructor...<BR>"); } } class b extends a { b(String s) throws java.io.IOException { localOut.println("In b\'s String constructor...<BR>"); localOut.println(s); } } %> <% localOut = out; b obj = new b("Hello from JSP!<BR>"); %> </BODY> </HTML> a b b a
Week 2 – Page 102
a
class a { a() { out.println("In a\'s constructor...<BR>"); } a(String s) { out.println("In a\'s String constructor...<BR>"); out.println(s); } } a super b String
Week 2 – Page 103
ch11_05.jsp
<HTML> <HEAD> <TITLE>Working With Constructors and Inheritance</TITLE> </HEAD> <BODY> <H1>Working With Constructors and Inheritance</H1> <%! javax.servlet.jsp.JspWriter localOut; class a { a() throws java.io.IOException { localOut.println("In a\'s constructor...<BR>"); } a(String s) throws java.io.IOException { localOut.println("In a\'s String constructor...<BR>"); localOut.println(s); } } class b extends a { b(String s) throws java.io.IOException { super(s); localOut.println("In b\'s String constructor...<BR>"); localOut.println(s); } } %> <% localOut = out; b obj = new b("Hello from JSP!<BR>"); %> </BODY> </HTML> b String a
Week 2 – Page 104
String a super String
b(String s) throws java.io.IOException { super(s); localOut.println("In b\'s String constructor...<BR>"); localOut.println(s); }
super
Week 2 – Page 105
Overloading Methods
print print(boolean b) print(char c) print(char[] s) print(double d) print(float f print(int i) print(long l) print
println
print
printText ch11_06.jsp
String
<HTML> <HEAD> <TITLE>Overloading Methods</TITLE> </HEAD> <BODY> <H1>Overloading Methods</H1> <%! javax.servlet.jsp.JspWriter localOut; void printText() throws java.io.IOException { localOut.println("Hello!<BR>"); } void printText(String s) throws java.io .IOException { localOut.println(s + "<BR>"); } %> <%
Week 2 – Page 106
localOut = out; printText(); printText("Hello from JSP!"); %> </BODY> </HTML>
Overriding Methods
final
breathe
breathe
animal Breathing...<BR>
class animal { public void breathe() { out.println("Breathing...<BR>"); } } animal trout Breathing...<BR> Gilling...<BR> trout
breathe
trout
breathe
class animal { public void breathe() { out.println("Breathing...<BR>"); } } class trout extends animal { public void breathe() {
Week 2 – Page 107
out.println("Gilling...<BR>"); } } breathe animal breathe ch11_07.jsp animal trout
<HTML> <HEAD> <TITLE>Overriding Methods</TITLE> </HEAD> <BODY> <H1>Overriding Methods</H1> <%! javax.servlet.jsp.JspWriter localOut; class animal { public void breathe() throws java.io.IOException { localOut.println("Breathing...<BR>"); } } class trout extends animal { public void breathe() throws java.io.IOException { localOut.println("Gilling...<BR>"); } } %> <% localOut = out; out.println("Creating an animal object...<BR>"); animal a = new animal(); a.breathe(); out.println(); out.println("Creating a trout object...<BR>"); trout t = new trout(); t.breathe(); %> </BODY> </HTML> breathe
Week 2 – Page 108
trout
Using Superclass Variables with Subclassed Objects
a a b a vehicle vehicle b
aircraft plane aircraft
class vehicle { public void start() {
Week 2 – Page 109
out.println("Starting...<BR>"); } } class aircraft extends vehicle { public void fly() { out.println("Flying...<BR>"); } } class plane extends aircraft { public void fly() { out.println("Flying...<BR>"); } } plane
out.println("Creating a plane...<BR>"); plane p = new plane(); p.start(); plane plane vehicle
ch11_08.jsp
<HTML> <HEAD> <TITLE>Using Superclass Variables With Subclassed Objects</TITLE> </HEAD> <BODY> <H1>Using Superclass Variables With Subclassed Objects</H1> <%! javax.servlet.jsp.JspWriter localOut; class vehicle { public void start() throws java.io.IOException { localOut.println("Starting...<BR>"); } }
Week 2 – Page 110
class aircraft extends vehicle { public void fly() throws java.io.IOException { localOut.println("Flying...<BR>"); } } class plane extends aircraft { public void fly() throws java.io.IOException { localOut.println("Flying...<BR>"); } } %> <% localOut = out; out.println("Creating a plane object...<BR>"); vehicle p = new plane(); p.start(); //p.fly(); %> </BODY> </HTML>
plane vehicle
Week 2 – Page 111
p.fly() fly vehicle vehicle a aircraft a b b plane
Using Runtime Polymorphism
a a b b c c d
Week 2 – Page 112
print
class a { public void print() { out.println("Hello from a...<BR>"); } } class b extends a { public void print() { out.println("Hello from b...<BR>"); } } class c extends a { public void print() { out.println("Hello from c...<BR>"); } } class d extends a { public void print() { out.println("Hello from d...<BR>"); } }
a b c d
a1 = b1 = c1 = d1 = . . .
new new new new
a(); b(); c(); d();
baseClassVariable
a
a b c d a
a1 = new a(); b1 = new b(); c1 = new c(); d1 = new d(); baseClassVariable;
Week 2 – Page 113
. . . baseClassVariable print print
out
ch11_09.jsp
<HTML> <HEAD> <TITLE>Runtime Polymorphism</TITLE> </HEAD> <BODY> <H1>Runtime Polymorphism</H1> <%! javax.servlet.jsp.JspWriter localOut; class a { public void print() throws java.io.IOException { localOut.println("Hello from a...<BR>"); } } class b extends a { public void print() throws java.io.IOException { localOut.println("Hello from b...<BR>"); } } class c extends a { public void print() throws java.io.IOException { localOut.println("Hello from c...<BR>"); } } class d extends a { public void print() throws java.io.IOException { localOut.println("Hello from d...<BR>"); } } %> <%
Week 2 – Page 114
localOut = out; a b c d a a1 = new a(); b1 = new b(); c1 = new c(); d1 = new d(); baseClassVariable;
baseClassVariable = a1; baseClassVariable.print(); baseClassVariable = b1; baseClassVariable.print(); baseClassVariable = c1; baseClassVariable.print(); baseClassVariable = d1; baseClassVariable.print(); %> </BODY> </HTML>
baseClassVariable
a b c
d
Week 2 – Page 115
a a a
Creating Abstract Classes
getMyName
abstract
a printem getText
printem
class a { String getText(); public void printem() { out.println(getText()); } } getText String getText()
Week 2 – Page 116
getText
abstract class a { abstract String getText(); public void printem() { out.println(getText()); } } a getText
class b extends a { String getText() { return "Hello from JSP!"; } }
ch11_10.jsp
<HTML> <HEAD> <TITLE>Using Abstract Classes</TITLE> </HEAD> <BODY> <H1>Using Abstract Classes</H1> <%! javax.servlet.jsp.JspWriter localOut;
Week 2 – Page 117
abstract class a { abstract String getText() throws java.io.IOException; public void printem() throws java.io.IOException { localOut.println(getText()); } } class b extends a { String getText() throws java.io.IOException { return "Hello from JSP!"; } } %> <% localOut = out; b bObject = new b(); bObject.printem(); %> </BODY> </HTML>
Week 2 – Page 118
Using Interfaces for Multiple Inheritance
extends
class a extends b, c { . . . }
// Will not work!
class a { .
Week 2 – Page 119
. . } class b extends a { . . . } class c extends b { . . . } c a b
interface
interface a { . . . } interface b { . . . } implements
class c implements a, b { . . . }
Week 2 – Page 120
printText
Printem interface
interface Printem { void printText(); } a
ch11_11.jsp
<HTML> <HEAD> <TITLE>Creating a Java Interface</TITLE> </HEAD> <BODY> <H1>Creating a Java Interface</H1> <%! javax.servlet.jsp.JspWriter localOut; interface Printem { void printText() throws java.io.IOException; } class a implements Printem { public void printText() throws java.io.IOException { localOut.println("Hello from JSP!"); } } %> <% localOut = out; a printer = new a(); printer.printText(); %> </BODY> </HTML>
Week 2 – Page 121
Summary
extends
public protected
private
Week 2 – Page 122
Q&A
super method1 super.method1
final
Workshop
Quiz
Week 2 – Page 123
class1 a d class2
a b e class1
c
class2
Exercises
SuperDuperCode getSupport SuperDuperCode SuperDuperCode
getSupport
a Printem Textem Printem Textem getText printText
Day 12. Creating Servlets
<jsp:plugin>
Week 2 – Page 124
<jsp:plugin>
Using <jsp:plugin>
.class <jsp:plugin>
+
<jsp:plugin type="bean|applet" code="classFileName" codebase="classFileDirectoryName" [name="Name"] [archive="ArchiveURL, ..."] [align="bottom|top|middle|left|right"] [height="{pixelMeasurement | <%= expression %>}"] [width="{pixelMeasurement | <%= expression %>}"] [hspace="leftRightPixels"] [vspace="topBottomPixels"] [jreversion="versionNumber | 1.2"] [nspluginurl="PluginURL"] [iepluginurl="PluginURL"]> [<jsp:params> [<jsp:param name="parameterName" value="{parameterValue | <%= expression %>}" /> ]+ </jsp:params> ] [<jsp:fallback> text </jsp:fallback> ] </jsp:plugin>
type="bean|applet" code="classFileName" codebase="classFileDirectoryName" <jsp:plugin>
Week 2 – Page 125
name="Name" archive="ArchiveURL, ..." align="bottom|top|middle|left|right" height="{pixelMeasurement | <%= expression %>}" width="{pixelMeasurement | <%= expression %>}" hspace="leftRightPixels" vspace="topBottomPixels"
jreversion="versionNumber|1.2" 1.2 nspluginurl="PluginURL" iepluginurl="PluginURL" <jsp:params> [<jsp:param name="parameterName" value="{parameterValue | <%= expression %>}" />]+ </jsp:params> <jsp:param> <jsp:params>
<jsp:fallback> text </jsp:fallback>
ch01_04.java
import java.applet.Applet; import java.awt.*; public class ch01_04 extends Applet { public void paint(Graphics g) { g.drawString("Hello there!", 60, 100); } } <APPLET> <jsp:plugin> <jsp:plugin>
<jsp:plugin>
ch12_01.jsp
<HTML> element> <HEAD> <TITLE>Using <jsp:plugin></TITLE> </HEAD>
Week 2 – Page 126
<BODY> <H1>Using <jsp:plugin></H1> <jsp:plugin type="applet" code="ch01_04.class" width="200" height="200" > <jsp:fallback> Sorry, <OBJECT> or <EMBED> are not supported by your browser. </jsp:fallback> </jsp:plugin> </BODY> </HTML>
<jsp:plugin>
<jsp:plugin> .class
Week 2 – Page 127
Creating Java Servlets
webapps work work jakarta-tomcat-4.0.3\work ch01 ch02 webapps <jsp:plugin> ch12_01.jsp jakarta-tomcat-4.0.3\work\ch12 ch12_01.jsp ch12_0005f01$jsp.java ch12_01.jsp <jsp:plugin> work
package org.apache.jsp; import import import import javax.servlet.*; javax.servlet.http.*; javax.servlet.jsp.*; org.apache.jasper.runtime.*;
public class ch12_0005f01$jsp extends HttpJspBase { static { } public ch12_0005f01$jsp( ) { } private static boolean _jspx_inited = false; public final void _jspx_init() throws org.apache.jasper.runtime.JspException {} public void _jspService(HttpServletRequest request, HttpServletResponse response) throws java.io.IOException, ServletException { JspFactory _jspxFactory = null; PageContext pageContext = null; HttpSession session = null; ServletContext application = null; ServletConfig config = null; JspWriter out = null; Object page = this; String _value = null; try {
Week 2 – Page 128
if (_jspx_inited == false) { synchronized (this) { if (_jspx_inited == false) { _jspx_init(); _jspx_inited = true; } } } _jspxFactory = JspFactory.getDefaultFactory(); response.setContentType("text/html;charset=IS O-8859-1"); pageContext = _jspxFactory.getPageContext(this, request, response, "", true, 8192, true); application = pageContext.getServletContext(); config = pageContext.getServletConfig(); session = pageContext.getSession(); out = pageContext.getOut(); // HTML // begin [file="/ch12_01.jsp";from=(0,0);to=(7,8)] out.write("<HTML>\r\n <HEAD>\r\n <TITLE> Using <jsp:plugin></TITLE>\r\n </HEAD>\r\n\r\n <BODY>\r\n <H1>Using <jsp:plugin></H1>\r\n "); // end // begin [file="/ch12_01.jsp";from=(7,8);to=(12,21)] /*Code generated for plugin*/ { out.println ("<OBJECT classid=\"clsid: 8AD9C840-044E-11D1B3E9-00805F499D93\" width=\"200\" height=\"200\" codebase=\"http://java.sun.com/products/plugin/1.2.2/ jinstall-1_2_2-win. cab#Version=1,2,2,0\">"); out.println ("<PARAM name=\"java_code\" value=\"ch01_04.class\">"); out.println ("<PARAM name=\"type\" value=\" application/xjava-applet;\">"); String _jspxString = null; String [][] _jspxNSString = null; int i = 0; out.println ("<COMMENT>"); out.print ("<EMBED type=\"application/x-java-applet;\" width=\"200\" height=\"200\" pluginspage=\"http://java.sun. com/products/plugin/\" java_code=\"ch01_04.class\" "); if (_jspxNSString != null) { for (i = 0; i < _jspxNSString.length; i++) { out.println ( _jspxNSString [i][0] + "=" + _ jspxNSString[i][1]); } } out.println (">"); out.println ("<NOEMBED>"); out.println ("</COMMENT>");
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out.println ("Sorry, <OBJECT> or < EMBED> are not supported by your browser.\r\n"); out.println ("</NOEMBED></EMBED>"); out.println ("</OBJECT>"); } // end // HTML // begin [file="/ch12_01.jsp";from=(12,21);to=(14,7)] out.write("\r\n </BODY>\r\n</HTML>"); // end } catch (Throwable t) { if (out != null && out.getBufferSize() != 0) out.clearBuffer(); if (pageContext != null) pageContext.handlePageException(t); } finally { if (_jspxFactory != null) _jspxFactory.releasePageContext (pageContext); } } }
ch01_06.java ch12_02.java
ch12_02.java
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch12_02 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println("<HTML>"); out.println("<HEAD>"); out.println("<TITLE>"); out.println("A Web Page"); out.println("</TITLE>"); out.println("</HEAD>"); out.println("<BODY>"); out.println("Hello there!"); out.println("</BODY>");
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out.println("</HTML>"); } }
servlet.jar jakarta-tomcat-4.0.3\common\lib directory CLASSPATH CLASSPATH servlet.jar
servlet.jar servlet.jar
C:\>SET CLASSPATH=C:\tomcat\jakarta-tomcat-4.0.3\common\lib\servlet.jar CLASSPATH servlet.jar CLASSPATH
C:>set classpath=%CLASSPATH%;C:\tomcat\jakarta-tomcat4.0.3\common\lib\servlet. jar servlet.jar ch12_02.java javac
javac
ch12_02.class
C:\tomcat\jakarta-tomcat-4.0.3\webapps\ch12\WEB-INF\classes>javac ch12_02.java ch12_02.class jakarta-tomcat4.0.3\webapps\ch12\classes http://localhost:8080/ch12/servlet/ch12_02
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http://localhost:8080/ch12/servlet/ch12_02
http://localhost:8080/ch12/ch12_02
HttpServlet
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch12_02 extends HttpServlet { . . . }
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HttpServlet
GenericServlet GenericServlet HttpServlet
GenericServlet
void destroy()
java.lang.String getInitParameter(java. lang.String name) java.util.Enumeration getInitParameterNames()
String
Enumeration ServletConfig getServletConfig() ServletContext getServletContext() java.lang.String getServletInfo() java.lang.String getServletName() void init()
String ServletConfig
ServletContext
super.init(config) void init(ServletConfig config)
void log(java.lang.String msg) void log(java.lang.String message,java.lang.Throwable t) abstract void service(ServletRequest req, ServletResponse res) HttpServlet
protected void doDelete(HttpServletRequest req,HttpServletResponse resp)
DELETE
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protected void doGet(HttpServletRequest req,HttpServletResponse resp) GET protected void doHead(HttpServletRequest req,HttpServletResponse resp) HEAD
protected void doOptions(HttpServletRequest req,HttpServletResponse resp)
OPTIONS
protected void doPost(HttpServletRequest req,HttpServletResponse resp) POST protected void doPut(HttpServletRequest req,HttpServletResponse resp) PUT protected void doTrace(HttpServletRequest req,HttpServletResponse resp) protected long getLastModified(HttpServletRequest req)
TRACE HttpServletRequest
protected void service(HttpServletRequest req,HttpServletResponse resp)
doXXX
void service(ServletRequest req,ServletResponse res)
protected service
request
doGet response
GET
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch12_02 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { //Handle requests... . .
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. //Configure responses... } } doGet GET POST doPost doGet GET GET service POST doGet doPost doGet doPost POST doPost POST
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch12_02 extends HttpServlet { public void service(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { //Handle requests... . . . //Configure responses... } . . .
response
Using the response Object
goGet doPost service HttpServletRequest request request HttpServletRequest
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response goGet doPost service HttpServletResponse
HttpServletResponse
out PrintWriter getWriter
JSPWriter out
PrintWriter setContentType
out
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch12_02 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println("<HTML>"); out.println("<HEAD>"); out.println("<TITLE>"); out.println("A Web Page"); out.println("</TITLE>"); out.println("</HEAD>"); out.println("<BODY>"); out.println("Hello there!"); out.println("</BODY>"); out.println("</HTML>"); } } println JspWriter PrintWriter PrintWriter PrintWriter
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PrintWriter(OutputStream out) OutputStream PrintWriter(OutputStream out, boolean autoFlush PrintWriter(Writer out)
PrintWriter
PrintWriter OutputStream PrintWriter
PrintWriter(Writer out boolean autoFlush boolean checkError() void close() void flush() void print(boolean b) void print(char c) void print(char[] s) void print(double d) void print(float f) void print(int i) void print(long l) void print(Object obj) void print(String s) void println() void println(boolean x) void println(char x) void println(char[] x) void println(double x) void println(float x) void println(int x) void println(long x)
PrintWriter
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void println(Object x) void println(String x) protected void setError() void write(char[] buf) void write(char[] buf int off, int len) void write(int c) void write(String s) void write(String s int off, int len)
Object String
Using the request Object
GET
doGet
ch12_03.html
<HTML> <HEAD> <TITLE>Using Text Fields With Servlets</TITLE> </HEAD> <BODY> <H1>Using Text Fields With Servlets</H1> <FORM NAME="form1" ACTION="servlet/ch12_04" METHOD="GET"> Enter your name: <INPUT TYPE="TEXT" NAME="name"> <INPUT TYPE="SUBMIT" VALUE="Click Me!"> </FORM> </BODY> </HTML>
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ch12_04.class request request
ACTION getParameter
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch12_04 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String name = request.getParameter("name"); . . .
ch12_04.java
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import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch12_04 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String name = request.getParameter("name"); response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println("<HTML>"); out.println("<HEAD>"); out.println("<TITLE>"); out.println("Using the request Object"); out.println("</TITLE>"); out.println("</HEAD>"); out.println("<BODY>"); out.println("<H1>"); out.println("Using the request Object"); out.println("</H1>"); out.println("Your name is " + name + "."); out.println("</BODY>"); out.println("</HTML>"); } }
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The Life Cycle of a Servlet
init destroy init
destroy
msg
init "Hello from Java servlets!"
String
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch12_05 extends HttpServlet { String msg = ""; public void init(ServletConfig config) {
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msg = "Hello from Java servlets!"; } . . . } msg msg ch12_05.java
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch12_05 extends HttpServlet { String msg = ""; public void init(ServletConfig config) { msg = "Hello from Java servlets!"; } public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println("<HTML>"); out.println("<HEAD>"); out.println("<TITLE>"); out.println("Using the init Method"); out.println("</TITLE>"); out.println("</HEAD>"); out.println("<BODY>"); out.println("<H1>Using the init Method</H1>"); out.println(msg); out.println("</BODY>"); out.println("</HTML>"); } } msg
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Creating Web Applications with Servlets
http://localhost:8080/ch12/servlet/ch12_02 .class
web.xml app>
<webweb.xml
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<web-app> <display-name> <servlet> <servlet-mapping>
<web-app> <icon> <display-name> <description> <distributable> <context-param> <servlet> <servlet-mapping> <session-config> <mime-mapping> <welcome-file-list> <error-page> <taglib> <resource-ref> <security-constraint> <login-config> <security-role> <env-entry> <ejb-ref> </web-app> web.xml ch12\WEB-INF <display-name>
web.xml
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd"> <web-app> <display-name>Example Applications</display-name> . . .
<display-name> getServletContextName
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<servlet> <servlet-class>
<servlet-name>
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd"> <web-app> <display-name>Example Applications</display-name> <servlet> <servlet-name>ch12_02</servlet-name> <servlet-class>ch12_02</servlet-class> </servlet> . . . <servlet-mapping> <url-pattern> <servlet-
name>
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd"> <web-app> <display-name>Example Applications</display-name> <servlet> <servlet-name>ch12_02</servlet-name> <servlet-class>ch12_02</servlet-class> </servlet> <servlet-mapping> <servlet-name>ch12_02</servlet-name> <url-pattern>/ch12_02</url-pattern> </servlet-mapping> <session-config> <session-timeout>30</session-timeout> </session-config> </web-app> <url-pattern> "/ch12_02" * "/data/*" ch12_02
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http://localhost:8080/ch12/ch12_02 http://localhost:8080/ch12/servlet/ch12_02
web.xml
Using Servlet Configurations and Contexts
javax.servlet.ServletConfig ServletConfig ServletContext javax.servlet.ServletContext
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<init-param> <param-value>
web.xml <servlet> <init-param> firstName lastName
<param-name>
Cary
Grant
web.xml
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd"> <web-app> <display-name>Example Applications</display-name> <servlet> <servlet-name>ch12_02</servlet-name> <servlet-class>ch12_02</servlet-class> </servlet> <servlet> <servlet-name>ch12_06</servlet-name> <servlet-class>ch12_06</servlet-class> <init-param> <param-name>firstName</param-name> <param-value>Cary</param-value> </init-param> <init-param> <param-name>lastName</param-name> <param-value>Grant</param-value> </init-param> </servlet> . . . ServletConfig GenericServlet getInitParameter firstName
public class ch12_06 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { response.setContentType("text/html"); PrintWriter out = response.getWriter();
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String firstName = getInitParameter("firstName") ; . . . ServletConfig getServletConfig lastName
ServletConfig
public class ch12_06 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); String firstName = getInitParameter("firstName"); ServletConfig configuration = getServletConfig(); String lastName = configuration.getInitParameter("lastName"); . . .
ServletContext
ServletContext
java.lang.Object getAttribute(java.lang.String name) java.util.Enumeration getAttributeNames()
Enumeration
ServletContext getContext(java.lang.String uripath)
ServletContext
java.lang.String getInitParameter(java.lang.String name)
String
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java.util.Enumeration getInitParameterNames() Enumeration int getMajorVersion() String
java.lang.String getMimeType (java.lang.String file) int getMinorVersion()
MIME
RequestDispatcher getNamedDispatcher(java.lang.String name) java.lang.String getRealPath(java.lang.String path)
RequestDispatcher String
RequestDispatcher getRequestDispatcher(java.lang.String path) java.net.URL getResource(java.lang.String path) java.io.InputStream getResourceAsStream(java.lang.String path) java.util.Set getResourcePaths(java.lang.String path)
RequestDispatcher
InputStream
java.lang.String getServerInfo() Servlet getServlet(java.lang.String name) java.lang.String getServletContextName() <display-name> java.util.Enumeration getServletNames() java.util.Enumeration getServlets()
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void log(java.lang.Exception exception java.lang.String msg)
log(String message, Throwable throwable)
void log(java.lang.String msg)
void log(java.lang.String message java.lang.Throwable throwable) void removeAttribute(java.lang.String name)
void setAttribute(java.lang.String name java.lang.Object object)
app>
web.xml <context-param>
<context-param> <web<param-name> <param-value> <init-param>
category Stars web.xml
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd"> <web-app> <display-name>Example Applications</display-name> <context-param> <param-name>category</param-name> <param-value>Stars</param-value> </context-param> <servlet> <servlet-name>ch12_02</servlet-name> <servlet-class>ch12_02</servlet-class> </servlet> <servlet> <servlet-name>ch12_06</servlet-name> <servlet-class>ch12_06</servlet-class> <init-param> <param-name>firstName</param-name> <param-value>Cary</param-value> </init-param> <init-param> <param-name>lastName</param-name>
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<param-value>Grant</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>ch12_02</servlet-name> <url-pattern>/ch12_02</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>ch12_06</servlet-name> <url-pattern>/ch12_06</url-pattern> </servlet-mapping> <session-config> <session-timeout>30</session-timeout> </session-config> </web-app>
GenericServlet ServletContext
getServletContext getInitParameter
ServletContext
firstName lastName category ch12_06.java
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch12_06 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); String firstName = getInitParameter("firstName"); ServletConfig configuration = getServletConfig(); String lastName = configuration.getInitParameter("lastName"); ServletContext context = getServletContext(); String category = context.getInitParameter("category"); out.println("<HTML>");
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out.println("<HEAD>"); out.println("<TITLE>"); out.println("Using Initialization Parameters"); out.println("</TITLE>"); out.println("</HEAD>"); out.println("<BODY>"); out.println("<H1>Using Initialization Parameters</H1>"); out.println("First Name: " + firstName); out.println("<BR>"); out.println("Last Name: " + lastName); out.println("<BR>"); out.println("Category: " + category); out.println("<BR>"); out.println("</BODY>"); out.println("</HTML>"); } }
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Summary
<jsp:plugin>
GET
POST
PrintWriter
getParameter response
init destroy
web.xml
Q&A
<jsp:plugin> <APPLET>
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setAttribute getAttribute application removeAttribute
Workshop
Quiz
<jsp:plugin>
GET
POST
goGet
doPost
Exercises
Week 2 – Page 154
<servlet> getServletContext
<web-app> setAttribute
web.xml getAttribute
Day 13. Creating More Powerful Servlets
Sessions and Servlet Contexts
Week 2 – Page 155
HTTPSession
public class ch13_01 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); HttpSession session = request.getSession(true); . . .
getAttribute counter
public class ch13_01 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); HttpSession session = request.getSession(true); Integer counter = (Integer) session.getAttribute("counter"); . . . counter
public class ch13_01 extends HttpServlet
Week 2 – Page 156
{ public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); HttpSession session = request.getSession(true); Integer counter = (Integer) session.getAttribute("counter"); if (counter == null) { counter = new Integer(1); } else { counter = new Integer(counter.intValue() + 1); } session.setAttribute("counter", counter); . . . isNew getLastAccessedTime getCreationTime getMaxInactiveInterval getID
ch13_01.java
import import import import
java.io.*; java.util.*; javax.servlet.*; javax.servlet.http.*;
public class ch13_01 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); HttpSession session = request.getSession(true); Integer counter = (Integer) session.getAttribute("counter"); if (counter == null) { counter = new Integer(1);
Week 2 – Page 157
} else { counter = new Integer(counter.intValue() + 1); } session.setAttribute("counter", counter); out.println("<HTML>"); out.println("<HEAD>"); out.println("<TITLE>"); out.println("Using Sessions"); out.println("</TITLE>"); out.println("</HEAD>"); out.println("<BODY>"); out.println("<H1>Using Sessions</H1>"); out.println("Welcome! You have been here " + counter + " times.<BR>"); if(session.isNew()){ out.println("This is a new session.<BR>"); } else { out.println("This is not a new session.< BR>"); } out.println("The session ID: " + session.getId() + "<BR>"); out.println("Last time accessed: " + new Date(session.getLastAccessedTime()) + " <BR>"); out.println("Creation time: " + new Date(session.getCreationTime()) + "<BR>"); out.println("Timeout length: " + session.getMaxInactiveInterval() + " s econds<BR>"); out.println("</BODY>"); out.println("</HTML>"); } }
Week 2 – Page 158
ServletContext
counter2 counter2 getServletContext getAttribute
public class ch13_02 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); HttpSession session = request.getSession(true); Integer counter2 = (Integer) getServletContext().getAttribute("counter2"); . . .
Week 2 – Page 159
counter2 counter2
public class ch13_02 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); HttpSession session = request.getSession(true); Integer counter2 = (Integer) getServletContext().getAttribute("counter2"); if (counter2 == null) { counter2 = new Integer(1); } else { counter2 = new Integer(counter2.intValue() + 1); } getServletContext().setAttribute("counter2", counter2); . . .
ch13_02.java
import import import import
java.io.*; java.util.*; javax.servlet.*; javax.servlet.http.*;
public class ch13_02 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); HttpSession session = request.getSession(true);
Week 2 – Page 160
Integer counter2 = (Integer) getServletContext().getAttribute("counter2"); if (counter2 == null) { counter2 = new Integer(1); } else { counter2 = new Integer(counter2.intValue() + 1); } getServletContext().setAttribute("counter2", counter2); Integer counter = (Integer) session.getAttribute("counter"); if (counter == null) { counter = new Integer(1); } else { counter = new Integer(counter.intValue() + 1); } session.setAttribute("counter", counter); out.println("<HTML>"); out.println("<HEAD>"); out.println("<TITLE>"); out.println("Using Contexts"); out.println("</TITLE>"); out.println("</HEAD>"); out.println("<BODY>"); out.println("<H1>Using Contexts</H1>"); out.println("Welcome! You have been here " + counter + " times.<BR>"); out.println("Total page accesses: " + counter2 + "<BR>"); if(session.isNew()){ out.println("This is a new session.<BR>"); } else { out.println("This is not a new session.<BR>"); } out.println("The session ID: " + session.getId() + "<BR>"); out.println("Last time accessed: " + new Date(session.getLastAccessedTime()) + "<BR>"); out.println("Creation time: " + new Date(session.getCreationTime()) + "<BR>"); out.println("Timeout length: " + session.getMaxInactiveInterval() + " seconds<BR>"); out.println("</BODY>"); out.println("</HTML>"); } }
Week 2 – Page 161
Forwarding Requests to Other Web Resources
servletID
"1"
public class ch13_03 extends HttpServlet {
Week 2 – Page 162
String target = "ch13_05"; public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setAttribute("servletID", "1"); . . . } }
RequestDispatcher HttpServletRequest getRequestDispatcher
ch13_05 http://localhost:8080/ch13/ch13_05 <servlet-mapping> web.xml
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch13_03 extends HttpServlet { String target = "ch13_05"; public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setAttribute("servletID", "1"); RequestDispatcher dispatcher = request.getRequestDispatcher(target); . . . } }
RequestDispatcher void forward(ServletRequest request, ServletResponse response)
void include(ServletRequest request, ServletResponse response)
Week 2 – Page 163
forward ch13_03.java
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch13_03 extends HttpServlet { String target = "ch13_05"; public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setAttribute("servletID", "1"); RequestDispatcher dispatcher = request.getRequestDispatcher(target); dispatcher.forward(request, response); } } include
<jsp:forward>
<HTML> <HEAD> <TITLE>Forwarding</TITLE> </HEAD> <BODY> <H1>Forwarding</H1> <% request.setAttribute("servletID", "1"); %> <jsp:forward page="ch13_05"/> </BODY> </HTML>
Week 2 – Page 164
Including Output from Other Web Resources
RequestDispatcher servletID 2 RequestDispatcher ch13_05 include
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch13_04 extends HttpServlet { String target = "ch13_05"; public void doGet(HttpServletRequest request, Htt pServletResponse response) throws ServletException, IOException { request.setAttribute("servletID", "2"); RequestDispatcher dispatcher = request.getRequestDispatcher(target); dispatcher.include(request, response); . . .
ch13_05
ch13_04.java
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch13_04 extends HttpServlet { String target = "ch13_05";
Week 2 – Page 165
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setAttribute("servletID", "2"); RequestDispatcher dispatcher = request.getRequestDispatcher(target); dispatcher.include(request, response); PrintWriter out = response.getWriter(); out.println("Response was included.<BR>"); } } include <jsp:include>
<jsp:include page="{relativeURL | <%= expression %>}" flush="true| false" /> <jsp:param> <jsp:forward>
<jsp:param>
<jsp:include page="{relativeURL | <%= expression %>}" flush="true| false" > <jsp:param name="parameterName" value="{parameterValue | <%= expression %>}" />+ </jsp:include>
page="{ relativeURL | <%= expression %> }" String
flush="true | false" true
flush
false <jsp:param name="parameterName" value="{parameterValue | <%= expression %>}" />+ <jsp:param>
<jsp:include>
<HTML> <HEAD> <TITLE>Includes</TITLE> </HEAD>
Week 2 – Page 166
<BODY> <H1>Includes</H1> <% request.setAttribute("servletID", "2"); %> <jsp:include page="ch13_05"/> Response was included. <BR> </BODY> </HTML>
Handling Forwards and Includes
ch13_03 ch13_04 servletID ch13_04 ch13_03
ch13_05.java
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch13_05 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String servletID = (String) request.getAttribute("servletID"); response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println("<HTML>"); out.println("<HEAD>"); out.println("<TITLE>"); out.println("Using Sessions"); out.println("</TITLE>"); out.println("</HEAD>"); out.println("<BODY>"); out.println("<H1>Using Forwards and Includes</H1><BR>");
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if (servletID != null) { if (servletID.equals("1")) { out.println("Forwarding was successful!<BR>"); } if (servletID.equals("2")) { out.println("Including was successful!<BR>"); } } else { out.println("This example must be invoked with ch13_03 or ch13_04"); } out.println("</BODY>"); out.println("</HTML>"); } } ch13_03
ch13_04
include
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JSP Model 1 Architecture
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JSP Model 2 Architecture
The Controller
model msg
public class ch13_06 extends HttpServlet {
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ch13_07 model1 = new ch13_07(); public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setAttribute("message", model1.msg()); . . .
ch13_06.java
import import import import
java.io.*; javax.servlet.*; javax.servlet.http.*; beans.ch13_07;
public class ch13_06 extends HttpServlet { String target = "ch13_08.jsp"; ch13_07 model1 = new ch13_07(); public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setAttribute("message", model1.msg()); RequestDispatcher dispatcher = request.getRequestDispatcher(target); dispatcher.forward(request, response); } }
The Model
msg "Hello from JSP!" ch13_07.java
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public class ch13_07 { public String msg() { return "Hello from JSP!"; } public ch13_07() { } }
The View
message
ch13_08.jsp
<HTML> <HEAD> <TITLE>Using MVC Architecture</TITLE> </HEAD> <BODY> <H1>Using MVC Architecture</H1> The message is <% out.println(request.getAttribute("message")); %> </BODY> </HTML> ch13_07.java ch13_06.class
ch13_07.class servlet.jar ch13_07.class
ch13_06.java
ch13_07.class WEB-INF\classes\beans
ch13 |____WEB-INF |____classes |____beans
ch13_08.jsp ch13_6.class ch13_07.class
. spath
classpath servlet.jar
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C:\tomcat\jakarta-tomcat-4.0.3\webapps\ch13\WEB-INF\classes>set classpath=spath\servlet. jar;. ch13_06.java ch13_6 web.xml javac
ch13_06 servlet
ch13_06 ch13_08
ch13_07
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Supporting User Authentication
web.xml users.xml web.xml <security-constraint> <web-app> <login-config>
tomcat-
<web-app> <icon> <display-name> <description> <distributable> <context-param> <servlet> <servlet-mapping> <session-config> <mime-mapping> <welcome-file-list> <error-page> <taglib> <resource-ref> <security-constraint> <login-config> <security-role> <env-entry> <ejb-ref> </web-app> <security-constraint>
<security-constraint> <web-resource-collection> <web-resource-name> <description> <url-pattern> <http-method> </web-resource-collection> <auth-constraint> <description> <role-name> </auth-constraint> <user-data-constraint> <description> <transport-guarantee> </user-data-constraint> </security-constraint>
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<login-config>
<login-config> <auth-method> <realm-name> </login-config>
tomcat-users.xml tomcat-users.xml
jakarta-tomcat-4.0.3\conf
<!-NOTE: By default, no user is included in the "manager" role required to operate the "/manager" web application. If you wish to use this app, you must define such a user - the username and password are arbitrary. --> <tomcat-users> <user name="tomcat" password="tomcat" roles="tomcat" /> <user name="role1" password="tomcat" roles="role1" /> <user name="both" password="tomcat" roles="tomcat,role1" /> <user name="steve" password="tomcat" roles="jsp" /> </tomcat-users> name <user> password roles
web.xml <security-constraint> <login-config>
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd"> <web-app> <display-name>Example Applications</display-name> <servlet> <servlet-name>ch13_01</servlet-name> <servlet-class>ch13_01</servlet-class> </servlet> <servlet> <servlet-name>ch13_02</servlet-name>
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<servlet-class>ch13_02</servlet-class> </servlet> <servlet> <servlet-name>ch13_03</servlet-name> <servlet-class>ch13_03</servlet-class> </servlet> <servlet> <servlet-name>ch13_04</servlet-name> <servlet-class>ch13_04</servlet-class> </servlet> <servlet> <servlet-name>ch13_05</servlet-name> <servlet-class>ch13_05</servlet-class> </servlet> . . . <session-config> <session-timeout>30</session-timeout> </session-config> <security-constraint> <web-resource-collection> <web-resource-name>Secure Area</web-resource-name> <url-pattern>/ch13_09</url-pattern> </web-resource-collection> <auth-constraint> <role-name>jsp</role-name> </auth-constraint> </security-constraint> <login-config> <auth-method>BASIC</auth-method> <realm-name>JSP Area</realm-name> </login-config> </web-app> web.xml <url-pattern> ch13_09 /secure/* secure * ch13_09
getAuthType getUserPrincipal Steve
BASIC
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ch13_09.java
import import import import import
java.io.*; java.util.*; java.security.*; javax.servlet.*; javax.servlet.http.*;
public class ch13_09 extends HttpServlet { public void init(ServletConfig cfg) throws ServletException { super.init(cfg); } public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println("<HTML>"); out.println("<HEAD>"); out.println("<TITLE>"); out.println("User Authentication"); out.println("</TITLE>"); out.println("</HEAD>"); out.println("<BODY>"); out.println("<H1>User Authentication</H1>"); String type = request.getAuthType(); out.println("Welcome to this secure page.<BR>"); out.println("Authentication mechanism: " + type + "<BR>"); Principal principal = request.getUserPrincipal(); out.println("Your username is: " + principal.getName() + "<BR>"); out.println("</BODY>"); out.println("</HTML>"); } }
tomcat-users.xml
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Using Cookies in Servlets
ch13_10.java
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch13_10 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println("<HTML>"); out.println("<HEAD>"); out.println("<TITLE>"); out.println("A Web Page"); out.println("</TITLE>"); out.println("</HEAD>"); out.println("<BODY"); Cookie[] cookies = request.getCookies(); boolean foundCookie = false; for(int loopIndex = 0; loopIndex < cookies.length; loopIndex++) { Cookie cookie1 = cookies[loopIndex];
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if (cookie1.getName().equals("color")) { out.println("bgcolor = " + cookie1.getValue()); foundCookie = true; } } if (!foundCookie) { Cookie cookie1 = new Cookie("color", "cyan"); cookie1.setMaxAge(24*60*60); response.addCookie(cookie1); } out.println(">"); out.println("<H1>Setting and Reading Cookies</H1>"); out.println("This page will set its background color using a cookie when reloaded. "); out.println("</BODY>"); out.println("</HTML>"); } } color "cyan"
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Thread Safety
static
SingleThreadModel service
public class servlet1 extends HttpServlet implements SingleThreadModel { . . . } page isThreadSafe true
false
synchronized shared synchronized
class CustomThread { Shared shared; public CustomThread(Shared shared, String string)
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{ super(string); this.shared = shared; start(); } public void run() { synchronized(shared) { shared.doWork(); } } }
Summary
getCookies
addCookie
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Q&A
Workshop
Quiz
web.xml
Exercises
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String
toUpper
*
<url-pattern>
Day 14. Using Filters
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Understanding Filters
javax.servlet.Filter init destroy doFilter doFilter
init
FilterConfig
javax.servlet.Filter
void destroy() void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) void init(FilterConfig filterConfig)
Creating a Simple Filter
ch14_01.java "Leaving ch14_01."
"In ch14_01."
Filter
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch14_01 implements Filter { . .
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. } Filter doFilter init init destroy
destroy
public class ch14_01 implements Filter { public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { . . . } public void destroy() { } public void init(FilterConfig filterConfig) { } } doFilter web.xml System.out.println doFilter doFilter
FilterChain
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { System.out.println("In ch14_01."); chain.doFilter(request, response); System.out.println("Leaving ch14_01."); } chain.doFilter
chain.doFilter chain.doFilter
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"In ch14_01." "Leaving ch14_01."
ch14_01.java
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch14_01 implements Filter { public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { System.out.println("In ch14_01."); chain.doFilter(request, response); System.out.println("Leaving ch14_01."); } public void destroy() { } public void init(FilterConfig filterConfig) { } }
ch14_02.java
import import import import
java.io.*; java.util.*; javax.servlet.*; javax.servlet.http.*;
public class ch14_02 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter();
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out.println("<HTML>"); out.println("<HEAD>"); out.println("<TITLE>"); out.println("Using a Simple Filter"); out.println("</TITLE>"); out.println("</HEAD>"); out.println("<BODY>"); out.println("<H1>Using a Simple Filter</H1>"); out.println("The simple filter will send text to the server console.<BR>"); out.println("</BODY>"); out.println("</HTML>"); } } servlet.jar classpath ch14\WEB-INF\classes ch14_02
ch14_01
web.xml web.xml <web-app> <filter> <filter-mapping>
<web-app> <icon> <display-name> <description> <distributable> <context-param> <filter> <filter-mapping> <servlet> <servlet-mapping> <session-config> <mime-mapping> <welcome-file-list> <error-page> <taglib> <resource-ref> <security-constraint> <login-config> <security-role> <env-entry> <ejb-ref> </web-app> <filter>
<filter> <filter-name> <filter-class>
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</filter> <filter-mapping>
<filter-mapping> <filter-name> <url-pattern> </filter-mapping> <filter>
<filter> <filter-name>Simple Filter</filter-name> <filter-class>ch14_01</filter-class> </filter> <filter-mapping> ch14_02
<filter-mapping> <filter-name>Simple Filter</filter-name> <url-pattern>/ch14_02</url-pattern> </filter-mapping> ch14_02 * ch14_02 <servlet-mapping>
<servlet> web.xml
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/j2ee/dtds/web-app_2_3.dtd"> <web-app> <filter> <filter-name>Simple Filter</filter-name> <filter-class>ch14_01</filter-class> </filter> <filter-mapping> <filter-name>Simple Filter</filter-name> <url-pattern>/ch14_02</url-pattern> </filter-mapping>
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<servlet> <servlet-name>ch14_02</servlet-name> <servlet-class>ch14_02</servlet-class> </servlet> <servlet-mapping> <servlet-name>ch14_02</servlet-name> <url-pattern>/ch14_02</url-pattern> </servlet-mapping> </web-app> ch14_02 http://localhost:8080/ch14/ch14_02
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Filtering JSP Pages
ch14_03.jsp
<HTML> <HEAD> <TITLE>Using a Simple Filter With JSP</TITLE> </HEAD> <BODY> <H1>Using a Simple Filter With JSP</H1> The simple filter will send text to the server console. <BR> </BODY> </HTML> ch14_01 ch14_03.jsp <filter-mapping> web.xml
<?xml version="1.0" encoding="ISO-8859-1"?>
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<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/j2ee/dtds/web-app_2_3.dtd"> <web-app> <filter> <filter-name>Simple Filter</filter-name> <filter-class>ch14_01</filter-class> </filter> <filter-mapping> <filter-name>Simple Filter</filter-name> <url-pattern>/ch14_02</url-pattern> </filter-mapping> <filter-mapping> <filter-name>Simple Filter</filter-name> <url-pattern>/ch14_03.jsp</url-pattern> </filter-mapping> <servlet> <servlet-name>ch14_02</servlet-name> <servlet-class>ch14_02</servlet-class> </servlet> <servlet-mapping> <servlet-name>ch14_02</servlet-name> <url-pattern>/ch14_02</url-pattern> </servlet-mapping> </web-app>
http://localhost:8080/ch14/ch14_03.jsp
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Starting service Tomcat-Apache Apache Tomcat/4.0.3 In ch14_01. Leaving ch14_01.
Creating Filter Chains
doFilter FilterChain chain
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { System.out.println("In ch14_01."); chain.doFilter(request, response); System.out.println("Leaving ch14_01."); }
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doFilter doFilter FilterChain Filter
"In ch14_04."
"Leaving ch14_04." ch14_01 ch14_04.java
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch14_04 implements Filter { public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { System.out.println("In ch14_04."); chain.doFilter(request, response); System.out.println("Leaving ch14_04."); } public void destroy() { } public void init(FilterConfig filterConfig) { } } web.xml
ch14_05.jsp
<HTML> <HEAD> <TITLE>Chaining Filters</TITLE> </HEAD> <BODY> <H1>Chaining Filters</H1>
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Both chained filters will send text to the server console. <BR> </BODY> </HTML> ch14_01 ch14_04 web.xml
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/j2ee/dtds/web-app_2_3.dtd"> <web-app> <filter> <filter-name>Simple Filter</filter-name> <filter-class>ch14_01</filter-class> </filter> <filter> <filter-name>Chained Filter</filter-name> <filter-class>ch14_04</filter-class> </filter> <filter-mapping> <filter-name>Simple Filter</filter-name> <url-pattern>/ch14_02</url-pattern> </filter-mapping> <filter-mapping> <filter-name>Simple Filter</filter-name> <url-pattern>/ch14_03.jsp</url-pattern> </filter-mapping> <filter-mapping> <filter-name>Simple Filter</filter-name> <url-pattern>/ch14_05.jsp</url-pattern> </filter-mapping> <filter-mapping> <filter-name>Chained Filter</filter-name> <url-pattern>/ch14_05.jsp</url-pattern> </filter-mapping> <servlet> <servlet-name>ch14_02</servlet-name> <servlet-class>ch14_02</servlet-class> </servlet> <servlet-mapping> <servlet-name>ch14_02</servlet-name> <url-pattern>/ch14_02</url-pattern> </servlet-mapping>
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</web-app> web.xml http://localhost:8080/ch14/ch14_05.jsp ch14_01 ch14_04
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Starting service Tomcat-Apache Apache Tomcat/4.0.3 In ch14_01. In ch14_04. Leaving ch14_04. Leaving ch14_01. ch14_01 ch14_04 ch14_01 ch14_01 ch14_04 ch14_01 ch14_04 ch14_04
Using Initialization Parameters
web.xml javax.servlet.FilterConfig doFilter javax.servlet.FilterConfig
javax.servlet.FilterConfig
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java.lang.String getFilterName() java.lang.String getInitParameter (java.lang.String name) String
java.util.Enumeration getInitParameterNames() Enumeration ServletContext getServletContext() String
<init-param>
<param-name>
<param-value>
<init-param> <param-name> <param-value> </init-param> <init-param> <filter>
<filter> <filter-name> <filter-class> <init-param> <param-name> <param-value> </init-param> <init-param> <param-name> <param-value> </init-param> <init-param> <param-name> <param-value> </init-param> </filter> FilterConfig doFilter init
public class ch14_06 implements Filter { private FilterConfig filterConfig = null; . .
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. public void init(FilterConfig filterConfig) { this.filterConfig = filterConfig; } } doFilter message ch14_06.java getInitParameter
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch14_06 implements Filter { private FilterConfig filterConfig = null; public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { System.out.println("The message is: " + filterConfig.getInitParameter("message")); chain.doFilter(request, response); } public void destroy() { } public void init(FilterConfig filterConfig) { this.filterConfig = filterConfig; } } message ch14_07.jsp
Hello!
web.xml
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/j2ee/dtds/web-app_2_3.dtd"> <web-app> <filter> <filter-name>Simple Filter</filter-name>
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<filter-class>ch14_01</filter-class> </filter> <filter> <filter-name>Chained Filter</filter-name> <filter-class>ch14_04</filter-class> </filter> <filter> <filter-name>Init Parameters Filter</filter-name> <filter-class>ch14_06</filter-class> <init-param> <param-name>message</param-name> <param-value>Hello!</param-value> </init-param> </filter> <filter-mapping> <filter-name>Simple Filter</filter-name> <url-pattern>/ch14_02</url-pattern> </filter-mapping> <filter-mapping> <filter-name>Simple Filter</filter-name> <url-pattern>/ch14_03.jsp</url-pattern> </filter-mapping> <filter-mapping> <filter-name>Simple Filter</filter-name> <url-pattern>/ch14_05.jsp</url-pattern> </filter-mapping> <filter-mapping> <filter-name>Chained Filter</filter-name> <url-pattern>/ch14_05.jsp</url-pattern> </filter-mapping> <filter-mapping> <filter-name>Init Parameters Filter</filter-name> <url-pattern>/ch14_07.jsp</url-pattern> </filter-mapping> <servlet> <servlet-name>ch14_02</servlet-name> <servlet-class>ch14_02</servlet-class> </servlet> <servlet-mapping> <servlet-name>ch14_02</servlet-name> <url-pattern>/ch14_02</url-pattern> </servlet-mapping> </web-app> ch14_07.jsp
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ch14_07.jsp
<HTML> <HEAD> <TITLE>Filters And Initialization Parameters</TITLE> </HEAD> <BODY> <H1>Filters And Initialization Parameters</H1> The initialization parameter's value will be displayed on the server console. <BR> </BODY> </HTML> http://localhost:8080/ch14/ch14_07.jsp
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Inserting Text Into the Response
getWriter PrintWriter
ch14_08.java
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch14_08 implements Filter { private FilterConfig filterConfig = null; public void doFilter(ServletRequest request, ServletResponse response,
Week 2 – Page 202
FilterChain chain) throws IOException, ServletException { chain.doFilter(request, response); response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println("The filter got this message: " + filterConfig.getInitParameter( " message")); } public void destroy() { } public void init(FilterConfig filterConfig) { this.filterConfig = filterConfig; } }
javax.servlet.http.HttpServletResponseWrapper
javax.servlet.http.HttpServletResponseWrapper
ch14_09.jsp
<HTML> <HEAD> <TITLE>Filters And Initialization Parameters</TITLE> </HEAD> <BODY> <H1>Filters And Initialization Parameters</H1> <BR> </BODY> </HTML>
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http://localhost:8080/ch14/ch14_09.jsp
Logging
ch14 <Context> server.xml <Context>
server.xml file <Host> <Context> server.xml
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<Context path="/ch14" docBase="ch14" debug="0" reloadable="true"> <Logger className="org.apache.catalina.logger.FileLogger" directory="logs" prefix="ch14." suffix=".txt" timestamp="true"/> </Context> <Context> ch14 28.txt log FilterConfig .txt ch14 jakarta-tomcat-4.0.3\logs ch14.2002-05-
getServletContext
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { chain.doFilter(request, response); filterConfig.getServletContext().log( . . . ); } request.getRemoteAddr request.getRequestURI doFilter doFilter
ch14_10.java
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class ch14_10 implements Filter { private FilterConfig filterConfig = null; public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
Week 2 – Page 205
long start = System.currentTimeMillis(); String address = request.getRemoteAddr(); String file = ((HttpServletRequest) request).getRequestURI(); chain.doFilter(request, response); filterConfig.getServletContext().log( "User access! " + " User IP: " + address + " Resource: " + file + " Milliseconds used: " + (System.currentTimeMillis( )start) ); } public void destroy() { } public void init(FilterConfig filterConfig) { this.filterConfig = filterConfig; } }
ch14_11.jsp
<HTML> <HEAD> <TITLE>Filters And Logging</TITLE> </HEAD> <BODY> <H1>Filters And Logging</H1> This filter writes to a log file. <BR> </BODY> </HTML> http://localhost:8080/ch14/ch14_11.jsp
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jakarta-tomcat4.0.3\logs\ch14.2002-05-28.txt
2002-05-28 12:06:37 WebappLoader[/ch14]: Deploying class repositories to work directory D: \tomcat\jakarta-tomcat-4.0.3\work\localhost\ch14 2002-05-28 12:06:37 WebappLoader[/ch14]: Reloading checks are enabled for this Context 2002-05-28 12:06:37 StandardManager[/ch14]: Seeding random number generator class java. security.SecureRandom 2002-05-28 12:06:37 StandardManager[/ch14]: Seeding of random number generator has been completed 2002-05-28 12:06:37 StandardWrapper[/ch14:default]: Loading container servlet default 2002-05-28 12:06:37 default: init 2002-05-28 12:06:37 StandardWrapper[/ch14:invoker]: Loading container servlet invoker 2002-05-28 12:06:37 invoker: init 2002-05-28 12:06:37 jsp: init 2002-05-28 12:06:46 jsp: init 2002-05-28 12:06:46 User access! User IP: 127.0.0.1 Resource: /ch14/ch14_11.jsp M illiseconds used: 100
Week 2 – Page 207
/ch14/ch14_11.jsp
Using Filters for User Authentication
password opensesame doFilter
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { String password = ((HttpServletRequest) request).getParameter("password"); if(password.equals("opensesame")) { chain.doFilter(request, response); } else { . . . } }
ch14_12.java
import java.io.*; import javax.servlet.*; import javax.servlet.http.*;
Week 2 – Page 208
public class ch14_12 implements Filter { private FilterConfig filterConfig = null; public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { String password = ((HttpServletRequest) request).getParameter("password"); if(password.equals("opensesame")) { chain.doFilter(request, response); } else { response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println("<HTML>"); out.println("<HEAD>"); out.println("<TITLE>"); out.println("Incorrect Password"); out.println("</TITLE>"); out.println("</HEAD>"); out.println("<BODY>"); out.println("<H1>Incorrect Password</H1>"); out.println("Sorry, that password was incorrect."); out.println("</BODY>"); out.println("</HTML>"); } } public void destroy() { } public void init(FilterConfig filterConfig) { this.filterConfig = filterConfig; } } ch14_13.html
ch14_13.html
<HTML> <HEAD> <TITLE>Using Passwords and Filters</TITLE> </HEAD> <BODY> <H1>Using Passwords and Filters</H1> <FORM ACTION="ch14_14.jsp" METHOD="POST"> Please enter your password: <INPUT TYPE="PASSWORD" NAME="password">
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<BR> <INPUT TYPE="SUBMIT" VALUE="Submit"> </FORM> </BODY> <HTML>
ch14_14.jsp
ch14_14.jsp
<HTML> <HEAD> <TITLE>Filters And User Authentication</TITLE> </HEAD> <BODY> <H1>Filters And User Authentication</H1> Congratulations, you're in! <BR> </BODY> </HTML>
http://localhost:8080/ch14/ch14_13.html
Week 2 – Page 210
ch14_14.jsp
Week 2 – Page 211
Restricting Access
Date
Calendar
ch14_15.java
import import import import
java.io.*; java.util.*; javax.servlet.*; javax.servlet.http.*;
Week 2 – Page 212
public class ch14_15 implements Filter { public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { GregorianCalendar calendar = new GregorianCalendar(); Date date1 = new Date(); calendar.setTime(date1); int hour = calendar.get(Calendar.HOUR_OF_DAY); if(hour < 9 || hour > 17) { chain.doFilter(request, response); } else { response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println("<HTML>"); out.println("<HEAD>"); out.println("<TITLE>"); out.println("Get Back to Work!"); out.println("</TITLE>"); out.println("</HEAD>"); out.println("<BODY>"); out.println("<H1>Get Back to Work!</H1>"); out.println("Sorry, that resource is not available now."); out.println("</BODY>"); out.println("</HTML>"); } } public void destroy() { } public void init(FilterConfig filterConfig) { } }
ch14_06.jsp ch14_16.jsp
<HTML> <HEAD> <TITLE>Using Filters to Restrict Access</TITLE> </HEAD> <BODY> <H1>Using Filters to Restrict Access</H1> Congratulations, you're in! <BR>
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</BODY> </HTML>
http://localhost:8080/ch14/ch14_16.jsp
Summary
web.xml
System.out.println
web.xml
Week 2 – Page 214
Q&A
Week 2 – Page 215
Workshop
Quiz
Filter
web.xml
Exercises
String toUpper
request.getHeader("User-Agent")
Week 2 – Page 216
