Jetty Jspc Maven Plugin

This plugin will pre-compile your JSP and works in conjunction with the Maven war plugin to put them inside an assembled war.

Configuration

Here’s the basic setup required to put the JSPC plugin into your build for the Jakarta EE ee10 environment:

<plugin>
  <groupId>org.eclipse.jetty.ee10</groupId>
   <artifactId>jetty-ee10-jspc-maven-plugin</artifactId>
   <version>12.0.15-SNAPSHOT</version>
   <executions>
     <execution>
       <id>jspc</id>
       <goals>
         <goal>jspc</goal>
       </goals>
       <configuration>
       </configuration>
     </execution>
   </executions>
 </plugin>

The configurable parameters are as follows:

webXmlFragment: Default value: ${project.basedir}/target/webfrag.xml

File into which to generate the servlet declarations. Will be merged with an existing web.xml.
webAppSourceDirectory: Default value: ${project.basedir}/src/main/webapp

Root of resources directory where jsps, tags etc are located.
webXml: Default value: ${project.basedir}/src/main/webapp/WEB-INF/web.xml

The web.xml file to use to merge with the generated fragments.
includes: Default value: **/*.jsp, **/*.jspx

The comma separated list of patterns for file extensions to be processed.
excludes: Default value: **/.svn/**

The comma separated list of patterns for file extensions to be skipped.
classesDirectory: Default value: ${project.build.outputDirectory}

Location of classes for the webapp.
generatedClasses: Default value: ${project.build.outputDirectory}

Location to put the generated classes for the jsps.
insertionMarker: Default value: none

A marker string in the src web.xml file which indicates where to merge in the generated web.xml fragment. Note that the marker string will NOT be preserved during the insertion. Can be left blank, in which case the generated fragment is inserted just before the line containing </web-app>.
useProvidedScope: Default value: false

If true, jars of dependencies marked with <scope>provided</scope> will be placed on the compilation classpath.
mergeFragment: Default value: true

Whether or not to merge the generated fragment file with the source web.xml. The merged file will go into the same directory as the webXmlFragment.
keepSources: Default value: false

If true, the generated .java files are not deleted at the end of processing.
scanAllDirectories: Default value: true

Determines if dirs on the classpath should be scanned as well as jars. If true, this allows scanning for tlds of dependent projects that are in the reactor as unassembled jars.
scanManifest: Default value: true

Determines if the manifest of JAR files found on the classpath should be scanned.
sourceVersion: Java version of jsp source files. The default value depends on the version of the jetty-ee10-jspc-maven-plugin.
targetVersion: Java version of class files generated from jsps. The default value depends on the version of the jetty-ee10-jspc-maven-plugin.
tldJarNamePatterns: Default value: .*taglibs[^/]*\.jar|.*jstl[^/]*\.jar$

Patterns of jars on the 'system' (ie container) path that contain tlds. Use | to separate each pattern.
jspc: Default value: the org.apache.jasper.JspC instance being configured.

The JspC class actually performs the pre-compilation. All setters on the JspC class are available.

Taking all the default settings, here’s how to configure the war plugin to use the generated web.xml that includes all of the jsp servlet declarations:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-war-plugin</artifactId>
  <configuration>
    <webXml>${project.basedir}/target/web.xml</webXml>
  </configuration>
</plugin>

Precompiling only for Production Build

As compiling jsps is usually done during preparation for a production release and not usually done during development, it is more convenient to put the plugin setup inside a <profile> which which can be deliberately invoked during prep for production.

For example, the following profile will only be invoked if the flag -Dprod is present on the run line:

<profiles>
  <profile>
    <id>prod</id>
    <activation>
      <property><name>prod</name></property>
    </activation>
    <build>
    <plugins>
      <plugin>
        <groupId>org.eclipse.jetty.ee10</groupId>
        <artifactId>jetty-ee10-jspc-maven-plugin</artifactId>
        <version>12.0.15-SNAPSHOT</version>
        <!-- put your configuration in here -->
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-war-plugin</artifactId>
        <!-- put your configuration in here -->
      </plugin>
    </plugins>
    </build>
  </profile>
</profiles>

The following invocation would cause your code to be compiled, the jsps to be compiled, the <servlet> and <servlet-mapping>s inserted in the web.xml and your webapp assembled into a war:

$ mvn -Dprod package

Precompiling Jsps with Overlaid Wars

Precompiling jsps with an overlaid war requires a bit more configuration. This is because you need to separate the steps of unpacking the overlaid war and then repacking the final target war so the jetty-ee10-jspc-maven-plugin has the opportunity to access the overlaid resources.

In the following example the overlaid war will provide the web.xml file but the jsps will be in src/main/webapp (i.e. part of the project that uses the overlay). The overlaid war file will be unpacked, the jsps compiled and their servlet definitions merged into the extracted web.xml, and everything packed into a war.

An example configuration of the war plugin that separates those phases into an unpack phase, and then a packing phase:

<plugin>
  <artifactId>maven-war-plugin</artifactId>
  <executions>
    <execution>
      <id>unpack</id>
      <goals><goal>exploded</goal></goals>
      <phase>generate-resources</phase>
      <configuration>
        <webappDirectory>target/foo</webappDirectory>
        <overlays>
          <overlay />
          <overlay>
            <groupId>org.eclipse.jetty.{ee-current}.demos</groupId>
            <artifactId>jetty-{ee-current}-demo-jetty-webapp</artifactId>
          </overlay>
        </overlays>
      </configuration>
    </execution>
    <execution>
      <id>pack</id>
      <goals><goal>war</goal></goals>
      <phase>package</phase>
      <configuration>
        <warSourceDirectory>target/foo</warSourceDirectory>
        <webXml>target/web.xml</webXml>
      </configuration>
    </execution>
  </executions>
</plugin>

Now you also need to configure the jetty-ee10-jspc-maven-plugin so that it can use the web.xml that was extracted by the war unpacking and merge in the generated definitions of the servlets. This is in target/foo/WEB-INF/web.xml. Using the default settings, the web.xml merged with the jsp servlet definitions will be put into target/web.xml.

<plugin>
  <groupId>org.eclipse.jetty.ee10</groupId>
   <artifactId>jetty-ee10-jspc-maven-plugin</artifactId>
   <version>12.0.15-SNAPSHOT</version>
   <executions>
     <execution>
       <id>jspc</id>
       <goals>
         <goal>jspc</goal>
       </goals>
       <configuration>
          <webXml>target/foo/WEB-INF/web.xml</webXml>
          <includes>**/*.foo</includes>
          <excludes>**/*.fff</excludes>
      </configuration>
    </execution>
  </executions>
</plugin>