今天在做SSI框架整合的时候报了一个这样的错误：Action class [userAction] not found - action - file:/D:/tomcat-6.0.29/webapps/SSIBlank/WEB-INF/classes/struts.xml:10:54，找了好久，一直以为我配置的问题或者是缓存的原因，翻来覆去搞了好久也没搞好，最后想想...原来是这样，具体的异常详细信息如下： 
严重: Exception starting filter Struts2.1 
Unable to load configuration. - action - file:/D:/tomcat-6.0.29/webapps/SSIBlank/WEB-INF/classes/struts.xml:10:54 
at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:431) 
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:295) 
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:4001) 
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4651) 
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791) 
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771) 
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:546) 
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1041) 
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:964) 
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:502) 
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1277) 
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:321) 
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119) 
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053) 
at org.apache.catalina.core.StandardHost.start(StandardHost.java:785) 
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045) 
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:445) 
at org.apache.catalina.core.StandardService.start(StandardService.java:519) 
at org.apache.catalina.core.StandardServer.start(StandardServer.java:710) 
at org.apache.catalina.startup.Catalina.start(Catalina.java:581) 
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) 
Caused by: Unable to load configuration. - action - file:/D:/tomcat-6.0.29/webapps/SSIBlank/WEB-INF/classes/struts.xml:10:54 
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:58) 
at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:374) 
at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:418) 
... 29 more 
Caused by: Action class [userAction] not found - action - file:/D:/tomcat-6.0.29/webapps/SSIBlank/WEB-INF/classes/struts.xml:10:54 
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.verifyAction(XmlConfigurationProvider.java:409)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addAction(XmlConfigurationProvider.java:354)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addPackage(XmlConfigurationProvider.java:468)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadPackages(XmlConfigurationProvider.java:264)
at org.apache.struts2.config.StrutsXmlConfigurationProvider.loadPackages(StrutsXmlConfigurationProvider.java:111)
at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:193) 
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:55) 
... 31 more 

    面对出现异常的情况一定要冷静的心态，不要看报了一大串异常就觉得无从下手，感到心烦意乱，其实报的异常越多说明你出现的问题越容易找（这是我自己的观点），哈哈...在看异常的时候抓住最后的Caused by，这才是引起异常的最终原因。 
下来看我们这个异常: 
检查步骤： 
1、看看你struts.xml文件中action中对应的class属性的值是否可以在Spring的配置文件中找到对应的id值。 
2、如果你确定你的配置没有出现问题，那么一定是你导入包的时候少了包，这时候你检查下你的项目中是否有以下三个jar包，struts2-spring-plugin-2.0.11.1.jar、commons-fileupload-1.2.1.jar和commons-io-1.3.2.jar。 
3、导入jar包之后如果还是有同样的错误，这时候你需要清理缓存或者把项目重新部署下，这样应该就可以解决问题了。