JSP页面错误

HTTP Status 500 - 

--------------------------------------------------------------------------------

type:Exception report

message 

description:The server encountered an internal error that prevented it from fulfilling this request.

exception 

java.lang.IllegalStateException
org.apache.catalina.connector.ResponseFacade.sendError(ResponseFacade.java:407)
org.apache.struts2.dispatcher.Dispatcher.sendError(Dispatcher.java:852)
org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:534)
org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)
cn.shop.Filter.EncodeFilter.doFilter(EncodeFilter.java:29)


note The full stack trace of the root cause is available in the Apache Tomcat/6.0.36 logs.


--------------------------------------------------------------------------------

Apache Tomcat/6.0.36




控制台报错
Servlet.service() for servlet default threw exception
java.lang.IllegalStateException
at org.apache.catalina.connector.ResponseFacade.sendError(ResponseFacade.java:407)
at org.apache.struts2.dispatcher.Dispatcher.sendError(Dispatcher.java:852)
at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:534)
at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at cn.shop.Filter.EncodeFilter.doFilter(EncodeFilter.java:29)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:861)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:606)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:745)

JSP页面跳转代码
<a href="${pageContext.request.contextPath}/userAction_saveUI.action">添加</a>
我的struts中有配置,UserAction中也有saveUI这个方法,但是就是不能出错,

<a href="${pageContext.request.contextPath}/userAction_queryUI.action">查询</a>都可以执行,不明白为什么出错!!求大神们指导!!