Tomcat6.X 配置Struts2 报错 “严重: Exception starting filter struts2”

开始使用Struts2 配置文件很容易出错。

2012-4-28 11:47:06 org.apache.catalina.core.StandardContext filterStart
严重: Exception starting filter struts2
java.lang.ClassNotFoundException: org.apache.struts2.dispatcher.ng
.filter.StrutsPrepareAndExecuteFilter
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1680)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1526)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:269)
at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:422)
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:115)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4072)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4726)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:799)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:779)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:601)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1079)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:1002)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:506)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1317)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:324)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:142)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1065)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:840)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1057)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:463)
at org.apache.catalina.core.StandardService.start(StandardService.java:525)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:754)
at org.apache.catalina.startup.Catalina.start(Catalina.java:595)
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:289)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)
2012-4-28 11:47:06 org.apache.catalina.core.StandardContext start
严重: Error filterStart
2012-4-28 11:47:06 org.apache.catalina.core.StandardContext start
严重: Context [/Struts2.0-1] startup failed due to previous errors

解决方法：

1. 检查jar包有没有完全导入，对于struts 2.3.1 需要导入9个包。

commons-fileupload-1.2.2.jar

commons-io-2.0.1.jar

commons-lang-2.5.jar

commons-logging-1.1.1.jar

freemarker-2.3.18.jar

javassist-3.11.0.GA.jar

ognl-3.0.4.jar

struts2-core-2.3.1.2.jar

xwork-core-2.3.1.2.jar

2. 检查web.xml, struts.xml配置文件

<?xml version="1.0" encoding="GBK"?>
<web-app version="3.0" 
	xmlns="http://java.sun.com/xml/ns/javaee"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
	http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
<filter>
	<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
	</filter>
<filter-mapping>
	<filter-name>struts2</filter-name>
	<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>

注意：配置 

<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>

必须一行写完中间不能有空格回车，否则就会出现Tomcat所报的错误。