container/webapps/docs/jasper-howto.xml - tomcat55 - Git at Google

 <?xml version="1.0"?>
 <!DOCTYPE document [
   <!ENTITY project SYSTEM "project.xml">
 ]>
 <document url="jasper-howto.html">

     &project;

     <properties>
         <author email="glenn@apache.org">Glenn L. Nielsen</author>
         <title>Jasper 2 JSP Engine How To</title>
     </properties>

 <body>

 <section name="Table of Contents">
 <p>
 <a href="#Introduction">Introduction</a><br />
 <a href="#Configuration">Configuration</a><br />
 <a href="#Production Configuration">Production Configuration</a><br />
 <a href="#Web Application Compilation">Web Application Compilation</a><br />
 <a href="#Using Jikes">Using Jikes</a><br />
 </p>
 </section>

 <section name="Introduction">

 <p>Tomcat 5.5 uses the Jasper 2 JSP Engine to implement
 the <a href="http://java.sun.com/products/jsp/">JavaServer Pages 2.0</a>
 specification.</p>

 <p>Jasper 2 has been redesigned to significantly improve performance over
 the orignal Jasper.  In addition to general code improvements the following
 changes were made:
 <ul>
 <li><strong>JSP Custom Tag Pooling</strong> - The java objects instantiated
 for JSP Custom Tags can now be pooled and reused.  This significantly boosts
 the performance of JSP pages which use custom tags.</li>
 <li><strong>Background JSP compilation</strong> - If you make a change to
 a JSP page which had already been compiled Jasper 2 can recompile that
 page in the background.  The previously compiled JSP page will still be
 available to serve requests.  Once the new page has been compiled
 successfully it will replace the old page.  This helps improve availablity
 of your JSP pages on a production server.</li>
 <li><strong>Recompile JSP when included page changes</strong> - Jasper 2
 can now detect when a page included at compile time from a JSP has changed
 and then recompile the parent JSP.</li>
 <li><strong>JDT used to compile JSP pages</strong> - The
 Eclipse JDT Java compiler is now used to perform JSP java source code
 compilation. This compiler loads source dependencies from the container
 classloader. Ant and javac can still be used.</li>
 </ul>
 </p>

 <p>Jasper is implemented using the servlet class
 <code>org.apache.jasper.servlet.JspServlet</code>.</p>

 </section>

 <section name="Configuration">

 <p>By default Jasper is configured for use when doing web application
 development.  See the section <a href="#Production Configuration">
 Production Configuration</a> for information on configuring Jasper
 for use on a production Tomcat server.</p>

 <p>The servlet which implements Jasper is configured using init parameters
 in your global <code>$CATALINA_BASE/conf/web.xml</code>.

 <ul>
 <li><strong>checkInterval</strong> - If development is false and reloading is
 true, background compiles are enabled. checkInterval is the time in seconds
 between checks to see if a JSP page needs to be recompiled. Default
 <code>300</code> seconds.</li>

 <li><strong>compiler</strong> - Which compiler Ant should use to compile JSP
 pages.  See the Ant documenation for more information. If the value is not set,
 then the default Eclipse JDT Java compiler will be used instead of using Ant.
 No default value.</li>

 <li><strong>classdebuginfo</strong> - Should the class file be compiled with
 debugging information?  <code>true</code> or <code>false</code>, default
 <code>true</code>.
 </li>

 <li><strong>classpath</strong> - What class path should I use while compiling
 generated servlets?  By default the classpath is created dynamically based on
 the current web application.</li>

 <li><strong>development</strong> - Is Jasper used in development mode (will
 check for JSP modification on every access)? <code>true</code> or
 <code>false</code>, default <code>true</code>.</li>

 <li><strong>enablePooling</strong> - Determines whether tag handler pooling is
 enabled. <code>true</code> or <code>false</code>, default <code>true</code>.
 </li>

 <li><strong>ieClassId</strong> - The class-id value to be sent to Internet
 Explorer when using &lt;jsp:plugin&gt; tags.   Default
 <code>clsid:8AD9C840-044E-11D1-B3E9-00805F499D93</code>.</li>

 <li><strong>fork</strong> - Have Ant fork JSP page compiles so they are
 performed in a seperate JVM from Tomcat? <code>true</code> or
 <code>false</code>, default <code>true</code>.</li>

 <li><strong>javaEncoding</strong> - Java file encoding to use for generating
 java source files. Default <code>UTF8</code>.</li>

 <li><strong>keepgenerated</strong> - Should we keep the generated Java source
 code for each page instead of deleting it? <code>true</code> or
 <code>false</code>, default <code>true</code>.</li>

 <li><strong>mappedfile</strong> - Should we generate static content with one
 print statement per input line, to ease debugging?
 <code>true</code> or <code>false</code>, default <code>true</code>.</li>

 <li><strong>reloading</strong> - Should Jasper check for modified JSPs?
 <code>true</code> or <code>false</code>, default <code>false</code>.</li>

 <li><strong>scratchdir</strong> - What scratch directory should we use when
 compiling JSP pages? Default is the work directory for the current web
 application.</li>

 <li><strong>trimSpaces</strong> - Should white spaces in template text between
 actions or directives be trimmed ?, default <code>false</code>.</li>
 </ul>
 </p>

 </section>

 <section name="Production Configuration">

 <p>When using Jasper 2 in a production Tomcat server you should consider
 making the following changes from the default configuration.
 <ul>
 <li><strong>development</strong> - To disable on access checks for JSP
 pages compilation set this to <code>false</code>.</li>
 <li><strong>fork</strong> - The internal JVM javac compiler used by Ant
 has a known memory leak. And Ant requires that java compiles be synchronized,
 i.e. only one JSP page can be compiled at a time.  Set fork to
 <code>true</code> or do not define it (it is the default value) so that Ant
 compiles JSP pages in a seperate JVM.
 This removes the synchronization of JSP page compiles and prevents
 all the javac classes from being instantiated and subsequently garbage
 collected by the JVM Tomcat is running in. This also works around known
 issues with javac, including memory leaking, as well as JAR file locking
 on Windows.</li>
 <li><strong>reloading</strong> - To disable background compilation of JSP
 pages, which uses one thread per web application, set this to
 <code>false</code>.</li>
 </ul>
 </p>

 </section>

 <section name="Web Application Compilation">

 <p>Using Ant is the preferred way to compile web applications using JSPC.
 Use the script given below to precompile a webapp:
 </p>

 <p>
 <source>
 &lt;project name="Webapp Precompilation" default="all" basedir="."&gt;

   &lt;target name="jspc"&gt;

     &lt;taskdef classname="org.apache.jasper.JspC" name="jasper2" &gt;
       &lt;classpath id="jspc.classpath"&gt;
         &lt;pathelement location="${java.home}/../lib/tools.jar"/&gt;
         &lt;fileset dir="${tomcat.home}/bin"&gt;
           &lt;include name="*.jar"/&gt;
         &lt;/fileset&gt;
         &lt;fileset dir="${tomcat.home}/server/lib"&gt;
           &lt;include name="*.jar"/&gt;
         &lt;/fileset&gt;
         &lt;fileset dir="${tomcat.home}/common/lib"&gt;
           &lt;include name="*.jar"/&gt;
         &lt;/fileset&gt;
       &lt;/classpath&gt;
     &lt;/taskdef&gt;

     &lt;jasper2
              validateXml="false"
              uriroot="${webapp.path}"
              webXmlFragment="${webapp.path}/WEB-INF/generated_web.xml"
              outputDir="${webapp.path}/WEB-INF/src" /&gt;

   &lt;/target&gt;

   &lt;target name="compile"&gt;

     &lt;mkdir dir="${webapp.path}/WEB-INF/classes"/&gt;
     &lt;mkdir dir="${webapp.path}/WEB-INF/lib"/&gt;

     &lt;javac destdir="${webapp.path}/WEB-INF/classes"
            optimize="off"
            debug="on" failonerror="false"
            srcdir="${webapp.path}/WEB-INF/src"
 	   excludes="**/*.smap"&gt;
       &lt;classpath&gt;
         &lt;pathelement location="${webapp.path}/WEB-INF/classes"/&gt;
         &lt;fileset dir="${webapp.path}/WEB-INF/lib"&gt;
           &lt;include name="*.jar"/&gt;
         &lt;/fileset&gt;
         &lt;pathelement location="${tomcat.home}/common/classes"/&gt;
         &lt;fileset dir="${tomcat.home}/common/lib"&gt;
           &lt;include name="*.jar"/&gt;
         &lt;/fileset&gt;
         &lt;pathelement location="${tomcat.home}/shared/classes"/&gt;
         &lt;fileset dir="${tomcat.home}/shared/lib"&gt;
           &lt;include name="*.jar"/&gt;
         &lt;/fileset&gt;
         &lt;fileset dir="${tomcat.home}/bin"&gt;
           &lt;include name="*.jar"/&gt;
         &lt;/fileset&gt;
       &lt;/classpath&gt;
       &lt;include name="**" /&gt;
       &lt;exclude name="tags/**" /&gt;
     &lt;/javac&gt;

   &lt;/target&gt;

   &lt;target name="all" depends="jspc,compile"&gt;
   &lt;/target&gt;

 &lt;/project&gt;
 </source>
 </p>

 <p>
 The following command line can be used to run the script
 (replacing the tokens with the Tomcat base path and the path to the webapp
 which should be precompiled):<br/>
 <source>
 $ANT_HOME/bin/ant -Dtomcat.home=&lt;$TOMCAT_HOME&gt; -Dwebapp.path=&lt;$WEBAPP_PATH&gt;
 </source>
 </p>

 <p>
 Then, the declarations and mappings for the servlets which were generated
 during the precompilation must be added to the web application deployment
 descriptor. Insert the <code>${webapp.path}/WEB-INF/generated_web.xml</code>
 at the right place inside the <code>${webapp.path}/WEB-INF/web.xml</code> file.
 Restart the web application (using the manager) and test it to verify it is
 running fine with precompiled servlets. An appropriate token placed in the
 web application deployment descriptor may also be used to automatically
 insert the generated servlet declarations and mappings using Ant filtering
 capabilities. This is actually how all the webapps distributed with Tomcat
 are automatically compiled as part of the build process.
 </p>

 </section>

 <section name="Using Jikes">

 <p>If you wish to use
 <a href="http://oss.software.ibm.com/developerworks/opensource/jikes/">
 Jikes</a> to compile JSP pages:
 <ul>
 <li>Download and install the Ant JAR in <code>$CATALINA_BASE/common/lib</code>.</li>
 <li>Download and install jikes. jikes must support the -encoding option.
 Execute <code>jikes -help</code> to verify that it was built with support
 for <code>-encoding</code>.</li>
 <li>Set the init parameter <code>compiler</code> to <code>jikes</code>.</li>
 <li>Define the property <code>-Dbuild.compiler.emacs=true</code> when starting
 Tomcat by adding it to your <code>CATALINA_OPTS</code> environment variable.
 This changes how jikes outputs error messages so that it is compatible with
 Jasper.</li>
 <li>If you get an error reporting that jikes can't use UTF8 encoding, try
 setting the init parameter <code>javaEncoding</code> to
 <code>ISO-8859-1</code>.</li>
 </ul>
 </p>

 </section>
 </body>

 </document>
	<?xml version="1.0"?>
	<!DOCTYPE document [
	<!ENTITY project SYSTEM "project.xml">
	]>
	<document url="jasper-howto.html">

	&project;

	<properties>
	<author email="glenn@apache.org">Glenn L. Nielsen</author>
	<title>Jasper 2 JSP Engine How To</title>
	</properties>

	<body>

	<section name="Table of Contents">
	<p>
	<a href="#Introduction">Introduction</a><br />
	<a href="#Configuration">Configuration</a><br />
	<a href="#Production Configuration">Production Configuration</a><br />
	<a href="#Web Application Compilation">Web Application Compilation</a><br />
	<a href="#Using Jikes">Using Jikes</a><br />
	</p>
	</section>

	<section name="Introduction">

	<p>Tomcat 5.5 uses the Jasper 2 JSP Engine to implement
	the <a href="http://java.sun.com/products/jsp/">JavaServer Pages 2.0</a>
	specification.</p>

	<p>Jasper 2 has been redesigned to significantly improve performance over
	the orignal Jasper. In addition to general code improvements the following
	changes were made:
	<ul>
	<li><strong>JSP Custom Tag Pooling</strong> - The java objects instantiated
	for JSP Custom Tags can now be pooled and reused. This significantly boosts
	the performance of JSP pages which use custom tags.</li>
	<li><strong>Background JSP compilation</strong> - If you make a change to
	a JSP page which had already been compiled Jasper 2 can recompile that
	page in the background. The previously compiled JSP page will still be
	available to serve requests. Once the new page has been compiled
	successfully it will replace the old page. This helps improve availablity
	of your JSP pages on a production server.</li>
	<li><strong>Recompile JSP when included page changes</strong> - Jasper 2
	can now detect when a page included at compile time from a JSP has changed
	and then recompile the parent JSP.</li>
	<li><strong>JDT used to compile JSP pages</strong> - The
	Eclipse JDT Java compiler is now used to perform JSP java source code
	compilation. This compiler loads source dependencies from the container
	classloader. Ant and javac can still be used.</li>
	</ul>
	</p>

	<p>Jasper is implemented using the servlet class
	<code>org.apache.jasper.servlet.JspServlet</code>.</p>

	</section>

	<section name="Configuration">

	<p>By default Jasper is configured for use when doing web application
	development. See the section <a href="#Production Configuration">
	Production Configuration</a> for information on configuring Jasper
	for use on a production Tomcat server.</p>

	<p>The servlet which implements Jasper is configured using init parameters
	in your global <code>$CATALINA_BASE/conf/web.xml</code>.

	<ul>
	<li><strong>checkInterval</strong> - If development is false and reloading is
	true, background compiles are enabled. checkInterval is the time in seconds
	between checks to see if a JSP page needs to be recompiled. Default
	<code>300</code> seconds.</li>

	<li><strong>compiler</strong> - Which compiler Ant should use to compile JSP
	pages. See the Ant documenation for more information. If the value is not set,
	then the default Eclipse JDT Java compiler will be used instead of using Ant.
	No default value.</li>

	<li><strong>classdebuginfo</strong> - Should the class file be compiled with
	debugging information? <code>true</code> or <code>false</code>, default
	<code>true</code>.
	</li>

	<li><strong>classpath</strong> - What class path should I use while compiling
	generated servlets? By default the classpath is created dynamically based on
	the current web application.</li>

	<li><strong>development</strong> - Is Jasper used in development mode (will
	check for JSP modification on every access)? <code>true</code> or
	<code>false</code>, default <code>true</code>.</li>

	<li><strong>enablePooling</strong> - Determines whether tag handler pooling is
	enabled. <code>true</code> or <code>false</code>, default <code>true</code>.
	</li>

	<li><strong>ieClassId</strong> - The class-id value to be sent to Internet
	Explorer when using <jsp:plugin> tags. Default
	<code>clsid:8AD9C840-044E-11D1-B3E9-00805F499D93</code>.</li>

	<li><strong>fork</strong> - Have Ant fork JSP page compiles so they are
	performed in a seperate JVM from Tomcat? <code>true</code> or
	<code>false</code>, default <code>true</code>.</li>

	<li><strong>javaEncoding</strong> - Java file encoding to use for generating
	java source files. Default <code>UTF8</code>.</li>

	<li><strong>keepgenerated</strong> - Should we keep the generated Java source
	code for each page instead of deleting it? <code>true</code> or
	<code>false</code>, default <code>true</code>.</li>

	<li><strong>mappedfile</strong> - Should we generate static content with one
	print statement per input line, to ease debugging?
	<code>true</code> or <code>false</code>, default <code>true</code>.</li>

	<li><strong>reloading</strong> - Should Jasper check for modified JSPs?
	<code>true</code> or <code>false</code>, default <code>false</code>.</li>

	<li><strong>scratchdir</strong> - What scratch directory should we use when
	compiling JSP pages? Default is the work directory for the current web
	application.</li>

	<li><strong>trimSpaces</strong> - Should white spaces in template text between
	actions or directives be trimmed ?, default <code>false</code>.</li>
	</ul>
	</p>

	</section>

	<section name="Production Configuration">

	<p>When using Jasper 2 in a production Tomcat server you should consider
	making the following changes from the default configuration.
	<ul>
	<li><strong>development</strong> - To disable on access checks for JSP
	pages compilation set this to <code>false</code>.</li>
	<li><strong>fork</strong> - The internal JVM javac compiler used by Ant
	has a known memory leak. And Ant requires that java compiles be synchronized,
	i.e. only one JSP page can be compiled at a time. Set fork to
	<code>true</code> or do not define it (it is the default value) so that Ant
	compiles JSP pages in a seperate JVM.
	This removes the synchronization of JSP page compiles and prevents
	all the javac classes from being instantiated and subsequently garbage
	collected by the JVM Tomcat is running in. This also works around known
	issues with javac, including memory leaking, as well as JAR file locking
	on Windows.</li>
	<li><strong>reloading</strong> - To disable background compilation of JSP
	pages, which uses one thread per web application, set this to
	<code>false</code>.</li>
	</ul>
	</p>

	</section>

	<section name="Web Application Compilation">

	<p>Using Ant is the preferred way to compile web applications using JSPC.
	Use the script given below to precompile a webapp:
	</p>

	<p>
	<source>
	<project name="Webapp Precompilation" default="all" basedir=".">

	<target name="jspc">

	<taskdef classname="org.apache.jasper.JspC" name="jasper2" >
	<classpath id="jspc.classpath">
	<pathelement location="${java.home}/../lib/tools.jar"/>
	<fileset dir="${tomcat.home}/bin">
	<include name="*.jar"/>
	</fileset>
	<fileset dir="${tomcat.home}/server/lib">
	<include name="*.jar"/>
	</fileset>
	<fileset dir="${tomcat.home}/common/lib">
	<include name="*.jar"/>
	</fileset>
	</classpath>
	</taskdef>

	<jasper2
	validateXml="false"
	uriroot="${webapp.path}"
	webXmlFragment="${webapp.path}/WEB-INF/generated_web.xml"
	outputDir="${webapp.path}/WEB-INF/src" />

	</target>

	<target name="compile">

	<mkdir dir="${webapp.path}/WEB-INF/classes"/>
	<mkdir dir="${webapp.path}/WEB-INF/lib"/>

	<javac destdir="${webapp.path}/WEB-INF/classes"
	optimize="off"
	debug="on" failonerror="false"
	srcdir="${webapp.path}/WEB-INF/src"
	excludes="*/.smap">
	<classpath>
	<pathelement location="${webapp.path}/WEB-INF/classes"/>
	<fileset dir="${webapp.path}/WEB-INF/lib">
	<include name="*.jar"/>
	</fileset>
	<pathelement location="${tomcat.home}/common/classes"/>
	<fileset dir="${tomcat.home}/common/lib">
	<include name="*.jar"/>
	</fileset>
	<pathelement location="${tomcat.home}/shared/classes"/>
	<fileset dir="${tomcat.home}/shared/lib">
	<include name="*.jar"/>
	</fileset>
	<fileset dir="${tomcat.home}/bin">
	<include name="*.jar"/>
	</fileset>
	</classpath>
	<include name="**" />
	<exclude name="tags/**" />
	</javac>

	</target>

	<target name="all" depends="jspc,compile">
	</target>

	</project>
	</source>
	</p>

	<p>
	The following command line can be used to run the script
	(replacing the tokens with the Tomcat base path and the path to the webapp
	which should be precompiled):<br/>
	<source>
	$ANT_HOME/bin/ant -Dtomcat.home=<$TOMCAT_HOME> -Dwebapp.path=<$WEBAPP_PATH>
	</source>
	</p>

	<p>
	Then, the declarations and mappings for the servlets which were generated
	during the precompilation must be added to the web application deployment
	descriptor. Insert the <code>${webapp.path}/WEB-INF/generated_web.xml</code>
	at the right place inside the <code>${webapp.path}/WEB-INF/web.xml</code> file.
	Restart the web application (using the manager) and test it to verify it is
	running fine with precompiled servlets. An appropriate token placed in the
	web application deployment descriptor may also be used to automatically
	insert the generated servlet declarations and mappings using Ant filtering
	capabilities. This is actually how all the webapps distributed with Tomcat
	are automatically compiled as part of the build process.
	</p>

	</section>

	<section name="Using Jikes">

	<p>If you wish to use
	<a href="http://oss.software.ibm.com/developerworks/opensource/jikes/">
	Jikes</a> to compile JSP pages:
	<ul>
	<li>Download and install the Ant JAR in <code>$CATALINA_BASE/common/lib</code>.</li>
	<li>Download and install jikes. jikes must support the -encoding option.
	Execute <code>jikes -help</code> to verify that it was built with support
	for <code>-encoding</code>.</li>
	<li>Set the init parameter <code>compiler</code> to <code>jikes</code>.</li>
	<li>Define the property <code>-Dbuild.compiler.emacs=true</code> when starting
	Tomcat by adding it to your <code>CATALINA_OPTS</code> environment variable.
	This changes how jikes outputs error messages so that it is compatible with
	Jasper.</li>
	<li>If you get an error reporting that jikes can't use UTF8 encoding, try
	setting the init parameter <code>javaEncoding</code> to
	<code>ISO-8859-1</code>.</li>
	</ul>
	</p>

	</section>
	</body>

	</document>