struts2.0 关于配置出错问题（QQ372690614）神啊救救我吧

事情是这样的 我配置完struts2.0后运行了下 hello.action和hello  没问题 然后我改下名字叫 <action name="hell">  先说下我已经配置了 <constant name="struts.devMode" value="true" />但是我运行hell.action和hell都出错  
大家有谁知道怎么解决吗  我是看尚学堂马士兵老师的视频跟着做的啊 为什么到这就是出错啊错误：Struts has detected an unhandled exception: Messages: There is no Action mapped for namespace / and action name hell. 
 
--------------------------------------------------------------------------------Stacktraces
There is no Action mapped for namespace / and action name hell. - [unknown location] 
    com.opensymphony.xwork2.DefaultActionProxy.prepare(DefaultActionProxy.java:178)
    org.apache.struts2.impl.StrutsActionProxy.prepare(StrutsActionProxy.java:61)
    org.apache.struts2.impl.StrutsActionProxyFactory.createActionProxy(StrutsActionProxyFactory.java:39)
    com.opensymphony.xwork2.DefaultActionProxyFactory.createActionProxy(DefaultActionProxyFactory.java:47)
    org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:478)
    org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
    org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)
    org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
    org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
    org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
    org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    java.lang.Thread.run(Unknown Source)