Struts2 严重: Dispatcher initialization failed java.lang.RuntimeException

严重: Dispatcher initialization failed
java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
 at com.opensymphony.xwork2.inject.ContainerImpl$MethodInjector.inject(ContainerImpl.java:295)
 at com.opensymphony.xwork2.inject.ContainerImpl$ConstructorInjector.construct(ContainerImpl.java:431)
 at com.opensymphony.xwork2.inject.ContainerBuilder$5.create(ContainerBuilder.java:207)
 at com.opensymphony.xwork2.inject.Scope$2$1.create(Scope.java:51)
 at com.opensymphony.xwork2.inject.ContainerBuilder$3.create(ContainerBuilder.java:93)
 at com.opensymphony.xwork2.inject.ContainerBuilder$7.call(ContainerBuilder.java:487)
 at com.opensymphony.xwork2.inject.ContainerBuilder$7.call(ContainerBuilder.java:484)
 at com.opensymphony.xwork2.inject.ContainerImpl.callInContext(ContainerImpl.java:574)
 at com.opensymphony.xwork2.inject.ContainerBuilder.create(ContainerBuilder.java:484)
 at com.opensymphony.xwork2.config.impl.DefaultConfiguration.createBootstrapContainer(DefaultConfiguration.java:252)
 at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:193)
 at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:66)
 at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:371)
 at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:415)
 at org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher(InitOperations.java:69)
 at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:51)
 at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:275)
 at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:397)
 at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:108)
 at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3800)
 at org.apache.catalina.core.StandardContext.start(StandardContext.java:4450)
 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)
Caused by: java.lang.reflect.InvocationTargetException

1、核对lib包

commons-fileupload-1.2.1.jar，
commons-io-1.3.2.jar
commons-logging-1.0.4.jar
freemarker-2.3.16.jar
ognl-3.0.jar
struts2-core-2.2.1.jar
xwork-core-2.2.1.jar

注意2.1以前是没有commons-fileupload-1.2.1.jar，

2、如果struts2版本是2.1以前

web.xml配置过滤器的时候应该是这样：

<web-app>
<filter>
<filter-name>struts2</filter-name>
<filter-class>

org.apache.struts2.dispatcher.FilterDispatcher
</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>


如果struts2 版本是2.1以上

web.xml配置

<web-app>
<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>
3、

在使用struts-2.2.1时，需要引入javassist-3.7.ga.jar，而这个在struts-2.2.1\lib下是没有的，需要在struts-2.2.1\apps\struts2-blank-2.2.1.war下的lib中找。
struts.xml文件头是从struts2-2.2.1-all\struts-2.2.1\apps里的任意文件拷贝的！