cannot load JSTL taglib within embedded Jetty server

Question

I am writing a web application that runs within an embedded Jetty instance.

When I attempt to execute a JSTL statement, I receive the following exception:

Answer 1

By adding the following code I got rid of the problem:

<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>jasper</artifactId>
    <version>6.0.29</version>
</dependency>

I am using jetty-runner 8.

Answer 2

I got the same problem on Jetty 7, I solved it by enabling Jetty to search for TLD:

I did it by setting an attribute on the context:

Server server = new Server(80);  
WebAppContext context = new WebAppContext("pig-1.0-SNAPSHOT.war","/");
context.setAttribute("org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern", 
    ".*/.*jsp-api-[^/]*\\.jar$|.*/.*jsp-[^/]*\\.jar$|.*/.*taglibs[^/]*\\.jar$");
server.addHandler(context);
server.start();

Refer to http://wiki.eclipse.org/Jetty/Howto/Configure_JSP#Using_JSTL_Taglibs_for_Jetty_7.x_and_8.x for further details.

On my project (using maven), I have standard TLDs are on the JAR "org.apache.taglibs.standard.glassfish-1.2.0.v2011120803.jar" and theoretically it would be enough to use as value for ContainerIncludeJarPattern the following pattern:

".*/org\\.apache\\.taglibs\\.standard\\.glassfish-1\\.2\\.0\\.v201112081803\\.jar"

It actually works and it is a confirmation of where do jetty found the tag libs, but I've preferred to leave the previous pattern which I found on the wiki.eclipse.org page linked above.

It may be required to extend the pattern if you want to include custom tag libs.

Answer 3

The jstl taglibs must be on server classpath. You can add a classloader to current classloader chain before start the server. That's the principle used by start.jar when it start a jetty server.

ClassLoader currentClassLoader = Thread.currentThread().getContextClassLoader();
URL urlTaglibs = new File(PATH_TO_TAGLIBS).toURI().toURL();
URLClassLoader newClassLoader = new URLClassLoader(new URL[]{urlTaglibs},currentClassLoader);
Thread.currentThread().setContextClassLoader(newClassLoader);

server.start();

You should also add it to java start command line argument.

Answer 4

Two step：

1）add annotation support for the server

//Enable parsing of jndi-related parts of web.xml and jetty-env.xml, #server is

org.eclipse.jetty.webapp.Configuration.ClassList classlist = org.eclipse.jetty.webapp.Configuration.ClassList.setServerDefault(server);
classlist.addAfter("org.eclipse.jetty.webapp.FragmentConfiguration", "org.eclipse.jetty.plus.webapp.EnvConfiguration", "org.eclipse.jetty.plus.webapp.PlusConfiguration");
classlist.addBefore("org.eclipse.jetty.webapp.JettyWebXmlConfiguration", "org.eclipse.jetty.annotations.AnnotationConfiguration");

2) add the follow attribute to the WebAppContext

context.setAttribute("org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern",".*/[^/]*servlet-api-[^/]*\\.jar$|.*/javax.servlet.jsp.jstl-.*\\.jar$|.*/org.apache.taglibs.taglibs-standard-impl-.*\\.jar$");