Class: com.opensymphony.xwork2.spring.SpringObjectFactory  File: SpringObjectFactory.java  Method: getClassInstance  Line: 220 - com/opensymphony/xwork2/spring/SpringObjectFactory.java:220:-1  at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:428)  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.
       
        (ApplicationFilterConfig.java:115)at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3838)  at org.apache.catalina.core.StandardContext.start(StandardContext.java:4488)  at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)  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:443)  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:585)  at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289)  at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)  Caused by: java.lang.NullPointerException  at com.opensymphony.xwork2.spring.SpringObjectFactory.getClassInstance(SpringObjectFactory.java:220)
       

Class: com.opensymphony.xwork2.spring.SpringObjectFactoryFile: SpringObjectFactory.javaMethod: getClassInstanceLine: 220 - com/opensymphony/xwork2/spring/SpringObjectFactory.java:220:-1	at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:428)	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.
      
       (ApplicationFilterConfig.java:115)	at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3838)	at org.apache.catalina.core.StandardContext.start(StandardContext.java:4488)	at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)	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:443)	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:585)	at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289)	at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)Caused by: java.lang.NullPointerException	at com.opensymphony.xwork2.spring.SpringObjectFactory.getClassInstance(SpringObjectFactory.java:220)
      

原因：

struts2导入的jar包中加入了struts-spring-plugin这个插件的jar

      			
       
        org.apache.struts
       			
       
        struts2-spring-plugin
       			
       
        2.2.1
       		
      

但是工程web.xml中没有配置加载spring ApplicationContext相关的listener

       
        
         org.springframework.web.context.ContextLoaderListener  
        
       

      	
       
        		org.springframework.web.context.ContextLoaderListener	
       
      

原理：

查看struts2插件struts2-spring-plugin中的strtus-plugin.xml

注意下面部分，表明该插件引入工程后，会自动设置Struts的ObjectFactory为StrutsSpringObjectFactory，从而让Spring的IOC容器来托管Struts的Action。所以导致了启动的问题。

记录一下错误，方便查看。