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Chapter 6. Configuring JSP Support

Table of Contents

Configuring JSP

Configuring JSP

This document provides information about configuring JSP.

Compiling JSPs

To compile .jsp files into Java classes, you need a Java compiler. You can acquire a Java compiler from the JVM if you are using a full JDK, or from a third party Jar.

In versions of Jetty prior to 7.5.0, the JSP infrastructure uses the Eclipse Java Compiler ( ecj.jar) which is supplied in $JETTY_HOME/lib/jsp. For jetty-7.5.0 and later we upgraded the version of JSP to jsp-impl-2.1.3.b10 (from Glassfish). In this version, the JSP infrastructure ALWAYS tries to acquire a Java compiler from the JVM if the version of Java is 1.6 or above. Therefore, if you are using a JRE, JSPs are unable to compile, so you must use a full JDK. Alternatively, you can precompile your JSPs (which is preferable in a production deployment in any case). The [[Jetty/Feature/Jetty_Jspc_Maven_Plugin|Jetty JSPC Maven Plugin]] TODO xref// is helpful for precompilation.

If you are using jetty-7.5.5 or later (including jetty-8.x), you can use either a full JDK or a JRE in combination with a third party Java compiler (such as ecj which we distribute in $JETTY_HOME/lib/jsp). To use the ecj compiler, you need to set a SystemProperty. You can do this either in your code or in a jetty config file. Here's the snippet that you can put into jetty.xml:


  <Call class="java.lang.System"  name="setProperty">
    <Arg>org.apache.jasper.compiler.disablejsr199</Arg>
    <Arg>true</Arg>
  </Call>

      

Alternatively, you can put this SystemProperty into start.ini:


 -Dorg.apache.jasper.compiler.disablejsr199=true

      

Using the Jetty Maven Plugin with JSP

For jetty-7.5.0 and later we upgraded the version of JSP to jsp-impl-2.1.3.b10 (from Glassfish). In this version, the JSP infrastructure ALWAYS tries to acquire a Java compiler from the JVM if the version of Java is 1.6 or above. Therefore, if you are using a JRE, JSPs are unable to compile, so you must use a full JDK.

We hope to be able to introduce a patch to allow the use of third party Jars in an upcoming release of the plugin. We will update this page when we have more information.

Configuring JSP for Jetty

The JSP engine has many configuration parameters. Some parameters affect only precompilation, and some affect runtime recompilation checking. Parameters also differ between the 2.0 and 2.1 release of the JSP engine. This page lists the configuration parameters, their meanings and their default settings.

Important

Be careful:

  • For all of the parameters below, if the value you set doesn't take effect, try using all lower case instead of camel case, as JSP is inconsistent in its parameter naming strategy.
  • Be aware that for JDK1.6, the default for keepgenerated is false; therefore .java files are left after compilation only if a compilation error occurs.

Table 6.1. Understanding JSP 2.1 Parameters

init paramDescriptionDefaultwebdefault.xml
developmentdevelopment=true, recompilation checks occur on each request. See also modificationTestInterval.TRUE
forkShould Ant fork its java compiles of JSP pages?TRUEFALSE
keepgeneratedDo you want to keep the generated Java files around?FALSE
saveByteCodeIf class files are generated as byte arrays, should they be saved to disk at the end of compilations?FALSE
trimSpacesShould white spaces between directives or actions be trimmed?FALSE
enablePoolingDetermines whether tag handler pooling is enabled.TRUE
mappedFileSupport for mapped Files. Generates a servlet that has a print statement per line of the JSP file./TRUE
sendErrorToClientIf false, stack traces, etc., are sent to std error instead of the client's browser.FALSE
classdebuginfoInclude debugging info in class file.TRUE
checkIntervalInterval in seconds between background recompile checks. Only relevant if development=false.0
suppressSmapGeneration of SMAP info for JSR45 debugging.FALSE
dumpSmapDump SMAP JSR45 info to a file.FALSE
genStrAsCharArrayOption for generating Strings.FALSE
genStrAsByteArrayOption for generating Strings.TRUE
defaultBufferNone FALSE
errorOnUseBeanInvalidClassAttribute FALSE
scratchDirDirectory where servlets are generated. Jetty sets this value according to the [/display/JETTY/Temporary+Directories work dir] settings for the webapp.
compilerDetermined at runtime. For Jetty this is the Eclipse jdt compiler.
compilerTargetVMTarget vm to compile for.1.5
compilerSourceVMSets source compliance level for the jdt compiler.1.5
javaEncodingPass through the encoding to use for the compilation.UTF8
modificationTestIntervalIf development=true, interval between recompilation checks, triggered by a request.0
xpoweredByGenerate an X-Powered-By response header.FALSEFALSE
usePrecompiled/use-precompiled FALSE
validating/enableTldValidationWhether or not to validate tag files against the schema.FALSE
reload-intervalIf reload-interval=0, then no runtime checking of JSP, otherwise sets the checking interval for both development=true and development=false.
initial-capacity/initialCapacityThe initial capacity of the hash maps mapping the name of the JSP to class and JSP file.

Much confusion generally ensues about the development, checkInterval and modificationTestInterval parameters and JSP runtime recompilation. Here is a factoring out of the various options:

  • Check the JSP files for possible recompilation on every request:
    
    <init-param>
            <param-name>development></param-name>
            <param-value>true></param-value>
    </init-param>
    
            
  • Only check approximately every N seconds, where a request will trigger the time-lapse calculation. This example checks every 60 seconds:
    
    <init-param>
            <param-name>development></param-name>
            <param-value>true></param-value>
    </init-param>
    <init-param>
            <param-name>modificationTestInterval></param-name>
            <param-value>60></param-value>
    </init-param>
    
            
  • Do no checking whatsoever, but still compile the JSP on the very first hit. (Note: this ''reload-interval'' parameter is shorthand for a ''development=false'' and ''checkInterval=0'' combination.):
    
    <init-param>
            <param-name>reload-interval></param-name>
            <param-value>-1></param-value>
    </init-param>
    
            
  • Don't do any request-time checking, but instead start a background thread to do checks every N seconds. This example checks every 60 seconds:
    
    <init-param>
            <param-name>development></param-name>
            <param-value>false></param-value>
     </init-param>
     <init-param>
             <param-name>checkInterval></param-name>
             <param-value>60></param-value>
    </init-param>
     
            

Modifying the Configuration

There are several options for modifying the Jasper JSP servlet configuration.

Overriding webdefault.xml

You can make a copy of the [[Jetty/Reference/webdefault.xml|webdefault.xml]] //TODO xref//that ships with Jetty, apply your changes, and use it instead of the shipped version. The example below shows how to do this when using the Jetty Maven plugin.


  <plugin>
    <groupId>org.mortbay.jetty</groupId>
    <artifactId>jetty-maven-plugin</artifactId>
    <configuration>
    <webAppConfig>
      <defaultsDescriptor>src/main/resources/webdefault.xml</defaultsDescriptor>
    </webAppConfig>
    <connectors>
    ..


        

If you're using Jetty standalone, and you want to change the JSP settings for just one or a few of your webapps, copy the $JETTY_HOME/etc/webdefault.xml file somewhere, modify it, and then use a [[Jetty/Feature/ContextDeployer|context xml]] //TODO xref// file to set this file as the webdefaults for your webapp. Here's a snippet:


 <Configure class=>"org.eclipse.jetty.webapp.WebAppContext">
 
   <Set name=>"contextPath">/foo</Set>
   <Set name=>"war"><SystemProperty name=>"jetty.home" >default=>"."/>/webapps/foobar.war</Set>
   <Set name=>"defaultsDescriptor">/home/smith/dev/webdefault.xml</Set>
  
 </Configure>

        

If you want to change the JSP settings for all of the webapps, edit the $JETTY_HOME/etc/webdefaults.xml file directly instead.

Configuring the JSP Servlet in web.xml

Another option is to add an entry for the Jasper JSP servlet to the web.xml file of your webapp. You can use the entry in [[Jetty/Reference/webdefault.xml|webdefault.xml]]//TODO xref// as a starting point.


 <servlet id=>"jsp">
     <servlet-name>jsp</servlet-name>
     <servlet-class>org.apache.jasper.servlet.JspServlet</servlet-class>
     <init-param>
         <param-name>logVerbosityLevel</param-name>
         <param-value>DEBUG</param-value>
     </init-param>
     <init-param>
         <param-name>fork</param-name>
         <param-value>>false</param-value>
     </init-param>
     <init-param>
         <param-name>keepgenerated</param-name>
         <param-value>>true</param-value>
     </init-param>
     ...
     
     <load-on-startup>0</load-on-startup>
   </servlet>
 
   <servlet-mapping>
     <servlet-name>jsp</servlet-name>
     <url-pattern>*.jsp</url-pattern>
     <url-pattern>*.jspf</url-pattern>
     <url-pattern>*.jspx</url-pattern>
     <url-pattern>*.xsp</url-pattern>
     <url-pattern>*.JSP</url-pattern>
     <url-pattern>*.JSPF</url-pattern>
     <url-pattern>*.JSPX</url-pattern>
     <url-pattern>*.XSP</url-pattern>
   </servlet-mapping>
   
   <servlet id=>"my-servlet">
     <servlet-name>myServlet</servlet-name>
     <servlet-class>com.acme.servlet.MyServlet</servlet-class>
      ...


        

Using JSTL Taglibs for Jetty 7.x and 8.x

There are some differences in how you use JSTL taglibs in Jetty 7 and Jetty 8.

Using JSTL Taglibs for Jetty 7.x

The JSTL tags are present in the org.apache.taglibs.standard.glassfish Jar in $JETTY_HOME/lib/jsp. For the Jetty/JSP integration to find them, you need to configure a pattern that defines the names of files in the container's classpath that contain .tld files. You must define the pattern as a context attribute on each context that you deploy. The context attribute and pattern is:


  attribute: org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern
  value: .*/.*jsp-api-[^/]*\.jar$|.*/.*jsp-[^/]*\.jar$|.*/.*taglibs[^/]*\.jar$

      

If you are using the Jetty deployers (that is, your start.ini file contains etc/jetty-deploy.xml), you don't need to do anything, as the pattern is pre-defined in etc/jetty-deploy.xml, and the deployer makes sure the attribute is set on each and every context it deploys. If you are NOT using the deployers, you need to configure the attribute on each context you set. Here's an example:


<New class="org.eclipse.jetty.webapp.WebAppContext">
  <Arg><Ref id="Contexts"/></Arg>
  <Arg><SystemProperty name="jetty.home" default="."/>/webapps/test.war</Arg>
  <Arg>/test</Arg>
   <Call name="setAttribute">
            <Arg>org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern</Arg>
            <Arg>.*/.*jsp-api-[^/]*\.jar$|.*/.*jsp-[^/]*\.jar$|.*/.*taglibs[^/]*\.jar$</Arg>
   </Call>
</New>

        

Note

You can use the org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern for more than identifying Jars that contain tlds. Its purpose is to supply a pattern of names of Jars on the container's classpath whose /META-INF directories should be scanned for resources, for fragments, or for TLDs.

Using JSTL Taglibs for Jetty 8.x

The version of JSP 2.2 engine that Jetty uses employs a Servlet 3.0 way of finding TLDs ( ServletContainerInitializer), and thus does not require that you define org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern.

Using JSF Taglibs

The following sections provide information about using JSF taglibs with Jetty Standalone and the Jetty Maven Plugin.

Using JSF Taglibs with Jetty Standalone

If you want to use JSF with your webapp, you need to copy the jsf implementation Jar (whichever Jar contains the META-INF/*.tld files from your chosen JSF implementation) into $JETTY_HOME/lib/jsp. This is because the version of the JSP engine from Glassfish that we are using requires that the JSF tags are on the container's classpath, and not on the webapp's classpath.

If you are using Jetty 7.x, add the JSF implementation Jar to the set of container Jars that are scanned for TLDs. The set of Jars is specified as a Java Pattern as the value of the ContextAttribute org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern. You must add a pattern that matches the name of the implementation Jar.

You can set this ContextAttribute on just a particular webapp, or for all webapps.

To set it on just one webapp, create or edit a [[Jetty/Feature/ContextDeployer|context xml]] //TODO xref// file that describes your webapp. For example, assuming the implementation Jar is called javax.faces-2.1.6.jar:


<Configure class="org.eclipse.jetty.webapp.WebAppContext">

    <Call name="setAttribute">
      <Arg>org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern</Arg>
      <Arg>.*/.*javax.faces-[^/]*\.jar$|.*/.*jsp-api-[^/]*\.jar$|.*/.*jsp-[^/]*\.jar$|.*/.*taglibs[^/]*\.jar$</Arg>
    </Call>

</Configure>

        

If you're deploying via code, the equivalent is to call the WebAppContext.setAttribute(String name, String value) method.

If you want to use JSF with all of your webapps, Using the Deployment Manager, edit $JETTY_HOME/etc/jetty-deploy.xml. For example, assuming the implementation Jar is named javax.faces-2.1.6.jar:


 <New id="DeploymentManager" class="org.eclipse.jetty.deploy.DeploymentManager">
          <Set name="contexts">
            <Ref id="Contexts" />
          </Set>
          <Call name="setContextAttribute">
            <Arg>org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern</Arg>
            <Arg>.*/.*javax.faces-[^/]*\.jar$|.*/.*jsp-api-[^/]*\.jar$|.*/.*jsp-[^/]*\.jar$|.*/.*taglibs[^/]*\.jar$</Arg>
          </Call>

        

If you are using Jetty 8.x you do not need to add this pattern because Servlet Spec. 3.0 uses a different method to find TLD descriptors.

Using JSF Taglibs with Jetty Maven Plugin

For Jetty versions prior to 7.5.0, your JSF Jars should be normal webapp dependencies. You do not need to do anything else to use Jetty with JSF.

From versions 7.5.0 and later, the version of the JSP engine from Glassfish that we are using requires that the JSF tags be on the container classpath, and not on the webapp classpath, so you need to make your JSF Jars dependencies of the plugin and not the webapp itself. For example:


   <plugin>
    <groupId>org.mortbay.jetty</groupId>
    <artifactId>jetty-maven-plugin</artifactId>
    <configuration>
       <webAppConfig>
         <contextPath>/jetty-documentation</contextPath>
       </webAppConfig>
       <scanIntervalSeconds>5</scanIntervalSeconds>
    </configuration>
    <dependencies>
      <dependency>
        <groupId>com.sun.faces</groupId>
        <artifactId>jsf-api</artifactId>
        <version>2.0.8</version>
      </dependency>
      <dependency>
        <groupId>com.sun.faces</groupId>
        <artifactId>jsf-impl</artifactId>
        <version>2.0.8</version>
     </dependency>
    </dependencies>
  </plugin>

        

For versions 7.5.0 to 7.6.1, the Jetty Maven plugin does not scan the JSF dependency Jars for the TLDs containing the startup listeners. If you are using these versions, we recommend you upgrade to a more recent version. If this is not possible, you should define the relevant listener in your web.xml:

For MyFaces:


 <listener>
     <listener-class>org.apache.myfaces.webapp.StartupServletContextListener</listener-class>
 </listener>

        

For Mojarra:


  <listener>
       <listener-class>com.sun.faces.config.ConfigureListener</listener-class>
    </listener>

        

For version 7.6.2 and later, the Jetty Maven plugin ensures that the TLDs containing the startup listeners from the two most common JSF implementations (Mojarra and MyFaces) are automatically detected.

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