ClassNotFoundException when running a Spring + Maven2 project on Tomcat 6 from within Eclipse 3.5

问题

When trying to launch a Web project from within Eclipse I get:


SEVERE: Error configuring application listener of class org.springframework.web.context.ContextLoaderListener
java.lang.ClassNotFoundException: org.springframework.web.context.ContextLoaderListener
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1387)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1233)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3877)
    at org.apache.catalina.core.StandardContext.start(StandardContext.java:4429)
    at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
    at org.apache.catalina.core.StandardHost.start(StandardHost.java:722)
    at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
    at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
    at org.apache.catalina.core.StandardService.start(StandardService.java:516)
    at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
    at org.apache.catalina.startup.Catalina.start(Catalina.java:583)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)
    at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)

Project started to fail when I switched to Fedora 12 x64. The project worked on WinXP with same configuration.

Googling around I found posts claiming that going to Project Properties -> Java EE Module Dependencies and checking the Maven Dependencies box fixes the issue. Sadly it didn't worked for me.

I'm using Spring 2.5.6, Maven2, Eclipse 3.5 (with the m2e 0.10.0 plugin), Tomcat 6 and Java 6 running on Fedora 12 x64.

Has anyone seen this problem?

In case it helps here is my .classpath file


<?xml version="1.0" encoding="UTF-8"?>
<classpath>
    <classpathentry kind="src" output="target/classes" path="src/main/java"/>
    <classpathentry kind="src" output="target/classes" path="target/generated-sources/gpb"/>
    <classpathentry excluding="**" kind="src" output="target/classes" path="src/main/resources"/>
    <classpathentry kind="src" output="target/test-classes" path="src/test/java"/>

    <classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.6"/>

    <classpathentry kind="con" path="org.maven.ide.eclipse.MAVEN2_CLASSPATH_CONTAINER">
        <attributes>
            <attribute name="org.eclipse.jst.component.dependency" value="/WEB-INF/lib"/>
        </attributes>
    </classpathentry>
    <classpathentry kind="con" path="org.eclipse.iam.jdt.core.mavenClasspathContainer">
        <attributes>
            <attribute name="org.eclipse.jst.component.dependency" value="/WEB-INF/lib"/>
        </attributes>
    </classpathentry>
    <classpathentry kind="con" path="org.eclipse.jst.j2ee.internal.web.container"/>
    <classpathentry kind="con" path="org.eclipse.jst.j2ee.internal.module.container"/>
    <classpathentry kind="output" path="target/classes"/>
</classpath>

Update: I don't have any problems building or running the project outside Eclipse.

回答1:

You seem to have both Eclipse IAM and M2Eclipse stuff in your .classpath. I would do some cleanup:

Use only one of these plugin (I suggest using M2Eclipse).
Delete your project from Eclipse's workspace, delete the .classpath and .project and Import the project as a Maven project again.

Update: To get WTP support with M2Eclipse, you need to install the Maven Integration for WTP from the m2eclipse Extras update site: http://download.eclipse.org/m2e-wtp/releases/ as illustrated below:

回答2:

I had the same symptom with a different cause. I had to edit my .classpath file. The maven entry:

<classpathentry kind="con" path="org.maven.ide.eclipse.MAVEN2_CLASSPATH_CONTAINER">
    <attributes>
        <attribute name="org.eclipse.jst.component.dependency" value="/WEB-INF/lib"/>
    </attributes>
</classpathentry>

...was lacking the attributes tag shown here. When I added the attributes tag the problem went away. I'm very curious how to configure that in the eclipse ui.