304 lines
18 KiB
HTML
304 lines
18 KiB
HTML
<html><head><META http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><title>Apache Tomcat 6.0 - Jasper 2 JSP Engine How To</title><meta name="author" value="Glenn L. Nielsen"><meta name="email" value="glenn@apache.org"><meta name="author" value="Peter Rossbach"><meta name="email" value="pero@apache.org"></head><body bgcolor="#ffffff" text="#000000" link="#525D76" alink="#525D76" vlink="#525D76"><table border="0" width="100%" cellspacing="0"><!--PAGE HEADER--><tr><td><!--PROJECT LOGO--><a href="http://tomcat.apache.org/"><img src="./../images/tomcat.gif" align="right" alt="
|
|
The Apache Tomcat Servlet/JSP Container
|
|
" border="0"></a></td><td><font face="arial,helvetica,sanserif"><h1>Apache Tomcat 6.0</h1></font></td><td><!--APACHE LOGO--><a href="http://www.apache.org/"><img src="./../images/asf-logo.gif" align="right" alt="Apache Logo" border="0"></a></td></tr></table><table border="0" width="100%" cellspacing="4"><!--HEADER SEPARATOR--><tr><td colspan="2"><hr noshade="noshade" size="1"></td></tr><tr><!--RIGHT SIDE MAIN BODY--><td width="80%" valign="top" align="left"><table border="0" width="100%" cellspacing="4"><tr><td align="left" valign="top"><h1>Apache Tomcat 6.0</h1><h2>Jasper 2 JSP Engine How To</h2></td><td align="right" valign="top" nowrap="true"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Table of Contents"><strong>Table of Contents</strong></a></font></td></tr><tr><td><blockquote>
|
|
<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>
|
|
</blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Introduction"><strong>Introduction</strong></a></font></td></tr><tr><td><blockquote>
|
|
|
|
<p>Tomcat 6.0 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>
|
|
|
|
</blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Configuration"><strong>Configuration</strong></a></font></td></tr><tr><td><blockquote>
|
|
|
|
<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 documentation 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> - Defines the class path to be used to compile
|
|
the generated servlets. This parameter only has an effect if the ServletContext
|
|
attribute org.apache.jasper.Constants.SERVLET_CLASSPATH is not set. This
|
|
attribute is always set when Jasper is used within Tomcat. By default the
|
|
classpath is created dynamically based on the current web application.</li>
|
|
|
|
<li><strong>compilerSourceVM</strong> - What JDK version are the source files compatible with? (Default JDK 1.4)</li>
|
|
|
|
<li><strong>compilerTargetVM</strong> - What JDK version are the generated files compatible with? (Default JDK 1.4)</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>engineOptionsClass</strong> - Allows specifying the Options class
|
|
used to configure Jasper. If not present, the default EmbeddedServletOptions
|
|
will be used.
|
|
</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>genStringAsCharArray</strong> - Should text strings be generated as char
|
|
arrays, to improve performance in some cases? Default <code>false</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>modificationTestInterval</strong> - Checks for modification for a given
|
|
JSP file (and all its dependent files) will be performed only once every specified amount
|
|
of seconds. Setting this to 0 will cause the JSP to be checked on every access.
|
|
Default is <code>4</code> seconds.</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>
|
|
|
|
<p>The Java compiler from Eclipse JDT in included as the default compiler. It is an
|
|
advanced Java compiler which will load all dependencies from the Tomcat class loader,
|
|
which will help tremendously when compiling on large installations with tens of JARs.
|
|
On fast servers, this will allow sub-second recompilation cycles for even large JSP
|
|
pages.</p>
|
|
|
|
<p>Apache Ant, which was used in previous Tomcat releases, can be used instead instead of
|
|
the new compiler by simply removing the <code>lib/jasper-jdt.jar</code> file,
|
|
and placing the <code>ant.jar</code> file from the latest Ant distribution in the
|
|
<code>lib</code> folder. If you do this, you also need to use the "javac"
|
|
argument to catalina.sh.</p>
|
|
|
|
</blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Production Configuration"><strong>Production Configuration</strong></a></font></td></tr><tr><td><blockquote>
|
|
|
|
<p>The main JSP optimization which can be done is precompilation of JSPs. However,
|
|
this might not be possible (for example, when using the jsp-property-group feature)
|
|
or practical, in which case the configuration of the Jasper servlet becomes critical.</p>
|
|
|
|
<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>genStringAsCharArray</strong> - To generate slightly more efficient
|
|
char arrays, set this to <code>true</code>.</li>
|
|
<li><strong>modificationTestInterval</strong> - If development has to be set to
|
|
<code>true</code> for any reason (such as dynamic generation of JSPs), setting
|
|
this to a high value will improve performance a lot.</li>
|
|
<li><strong>trimSpaces</strong> - To remove useless bytes from the response,
|
|
set this to <code>true</code>.</li>
|
|
</ul>
|
|
</p>
|
|
|
|
</blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Web Application Compilation"><strong>Web Application Compilation</strong></a></font></td></tr><tr><td><blockquote>
|
|
|
|
<p>Using Ant is the preferred way to compile web applications using JSPC.
|
|
Use the script given below (a similar script is included in the "deployer"
|
|
download) to precompile a webapp:
|
|
</p>
|
|
|
|
<p>
|
|
<div align="left"><table cellspacing="4" cellpadding="0" border="0"><tr><td bgcolor="#023264" width="1" height="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" height="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" width="1" height="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td></tr><tr><td bgcolor="#023264" width="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#ffffff" height="1"><pre>
|
|
<project name="Webapp Precompilation" default="all" basedir=".">
|
|
|
|
<import file="${tomcat.home}/bin/catalina-tasks.xml"/>
|
|
|
|
<target name="jspc">
|
|
|
|
<jasper
|
|
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}/lib"/>
|
|
<fileset dir="${tomcat.home}/common/lib">
|
|
<include name="*.jar"/>
|
|
</fileset>
|
|
<fileset dir="${tomcat.home}/bin">
|
|
<include name="*.jar"/>
|
|
</fileset>
|
|
</classpath>
|
|
<include name="**" />
|
|
<exclude name="tags/**" />
|
|
</javac>
|
|
|
|
</target>
|
|
|
|
<target name="all" depends="jspc,compile">
|
|
</target>
|
|
|
|
<target name="cleanup">
|
|
<delete>
|
|
<fileset dir="${webapp.path}/WEB-INF/src"/>
|
|
<fileset dir="${webapp.path}/WEB-INF/classes/org/apache/jsp"/>
|
|
</delete>
|
|
</target>
|
|
|
|
</project>
|
|
</pre></td><td bgcolor="#023264" width="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td></tr><tr><td bgcolor="#023264" width="1" height="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" height="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" width="1" height="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td></tr></table></div>
|
|
</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>
|
|
<div align="left"><table cellspacing="4" cellpadding="0" border="0"><tr><td bgcolor="#023264" width="1" height="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" height="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" width="1" height="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td></tr><tr><td bgcolor="#023264" width="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#ffffff" height="1"><pre>
|
|
$ANT_HOME/bin/ant -Dtomcat.home=<$TOMCAT_HOME> -Dwebapp.path=<$WEBAPP_PATH>
|
|
</pre></td><td bgcolor="#023264" width="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td></tr><tr><td bgcolor="#023264" width="1" height="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" height="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" width="1" height="1"><img src="./../images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"></td></tr></table></div>
|
|
</p>
|
|
|
|
<p>
|
|
Then, the declarations and mappings for the servlets which were generated
|
|
during the precompilation must be added to the web application deployment
|
|
descriptor. Insert the <code>${webapp.path}/WEB-INF/generated_web.xml</code>
|
|
at the right place inside the <code>${webapp.path}/WEB-INF/web.xml</code> file.
|
|
Restart the web application (using the manager) and test it to verify it is
|
|
running fine with precompiled servlets. An appropriate token placed in the
|
|
web application deployment descriptor may also be used to automatically
|
|
insert the generated servlet declarations and mappings using Ant filtering
|
|
capabilities. This is actually how all the webapps distributed with Tomcat
|
|
are automatically compiled as part of the build process.
|
|
</p>
|
|
|
|
<p>
|
|
At the jasper2 task you can use the option <code>addWebXmlMappings</code> for
|
|
automatic merge the <code>${webapp.path}/WEB-INF/generated_web.xml</code>
|
|
with the current web application deployment descriptor at <code>${webapp.path}/WEB-INF/web.xml</code>.
|
|
When you want to use Java 5 feature inside your jsp's, add the following javac compiler task
|
|
attributes: <code>source="1.5" target="1.5"</code>. For live application
|
|
you can also compile with <code>optimize="on"</code> and without debug info
|
|
<code>debug="off"</code>.
|
|
</p>
|
|
|
|
<p>
|
|
When you don't want to stop the jsp generation at first jsp syntax error, use
|
|
<code>failOnError="false"</code>and with <code>showSuccess="true"</code>
|
|
all successfull <i>jsp to java</i> generation are printed out. Sometimes it is
|
|
very helpfull, when you cleanup the generate java source files at <code>${webapp.path}/WEB-INF/src</code>
|
|
and the compile jsp servlet classes at <code>${webapp.path}/WEB-INF/classes/org/apache/jsp</code>.
|
|
</p>
|
|
|
|
<p><strong>Hints:</strong>
|
|
<ul>
|
|
<li> When you switch to another tomcat release, then regenerate and recompile
|
|
your jsp's with this version again!</li>
|
|
<li>Use java system property at server runtime to disable tag pooling <code>org.apache.jasper.runtime.JspFactoryImpl.USE_POOL=false</code>.
|
|
and limit the buffering with <code>org.apache.jasper.runtime.BodyContentImpl.LIMIT_BUFFER=true</code>. Note that changing
|
|
from the defaults may affect performance, but depending on the application.</li>
|
|
</ul>
|
|
</p>
|
|
</blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Using Jikes"><strong>Using Jikes</strong></a></font></td></tr><tr><td><blockquote>
|
|
|
|
<p>If you wish to use
|
|
<a href="http://oss.software.ibm.com/developerworks/opensource/jikes/">
|
|
Jikes</a> to compile JSP pages:
|
|
<ul>
|
|
<li>From your <a href="ant.apache.org">Ant</a> installation, copy ant.jar
|
|
and (if it's available: Ant 1.5 and later) ant-launcher.jar to
|
|
<code>$CATALINA_BASE/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>
|
|
|
|
</blockquote></td></tr></table></td></tr><!--FOOTER SEPARATOR--><tr><td colspan="2"><hr noshade="noshade" size="1"></td></tr><!--PAGE FOOTER--><tr><td colspan="2"><div align="center"><font color="#525D76" size="-1"><em>
|
|
Copyright © 1999-2006, Apache Software Foundation
|
|
</em></font></div></td></tr></table></body></html> |