I am trying to figure out the best way to use Ant to precompile JSPs that will be deployed to an Oracle application server. Even though I am deploying to an Oracle app server I would like to avoid using Oracle's version of Ant.

Oracle's JSP compiler is available in your oc4j install at ORACLE_HOME/j2ee/home/jsp/bin/ojspc

Assuming your classpath is correct at the compand line you would run:

ojspc your.war

The war will get updated and place a jar in the WEB-INF/lib containing the pre-compiled JSPs. Note that if your pre-compiling JSPs you should also set the MAIN_MODE to 'JUSTRUN' to get the additional performance benefit of pre-compiling your JSPs. The JUSTRUN setting does what it implies, the OC4J container will no longer check for updated .jsp files.

<servlet>
    <servlet-name>jsp</servlet-name>
    <servlet-class>oracle.jsp.runtimev2.JspServlet</servlet-class>
    <init-param>
      <param-name>main_mode</param-name>
      <param-value>justrun</param-value>
    </init-param>
</servlet>

Once your comfortable with calling ojspc from the command line You can then begin to use the ANT tasks provided by Oracle.

Within ANT

<oracle:compileJsp file="dist/war/before-${app}war"
        verbose="false"
        output="dist/war/${app}.war" />

Your project tag should reference the oracle tasks:

<project name="your-name" default="compile" basedir="."  xmlns:oracle="antlib:oracle">
...
</project>

Update 02.22.2011 You can also just work with the ojspc jar directly and avoid trying to configure the oracle:compileJsp Task, the code below takes a war file and pre-compiles the JSPS in it.

 <!-- Now Precompile the War File (see entry in <project> tag ) -->
    <java jar="${env.ORACLE_HOME}/j2ee/home/ojspc.jar" classpathref="jspPreCompileClassPath" fork="true">
        <arg value="-addClasspath"/>
        <arg pathref="classpath"/>
        <arg line="'${dist}/war/a-war-file.war'"/>
    </java>

the jspPreCompileClassPath defnition looks like this:

  <path id="jspPreCompileClassPath">
    <path location="${env.ORACLE_HOME}/j2ee/home/lib/pcl.jar"/>
    <path location="${env.ORACLE_HOME}/j2ee/home/lib/ojsp.jar"/>
    <path location="${env.ORACLE_HOME}/j2ee/home/lib/oc4j-internal.jar"/>
    <path location="${env.ORACLE_HOME}/j2ee/home/lib/servlet.jar"/>
    <path location="${env.ORACLE_HOME}/j2ee/home/lib/commons-el.jar"/>
    <path location="${env.ORACLE_HOME}/j2ee/home/lib/bcel.jar"/>
    <path location="${env.ORACLE_HOME}/lib/xmlparserv2.jar"/>
    <path location="${env.ORACLE_HOME}/j2ee/home/lib/oc4j-schemas.jar"/>
    <path location="${env.ORACLE_HOME}/j2ee/home/jsp/lib/taglib/ojsputil.jar"/>
  </path>

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