项目中出现的问题,记录一下

环境：Struts2、Spring、Hibernate、Freemarker。
场景：在执行完Action，重定向到一个Action时报错。
错误：

2012-5-23 9:51:41 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet [default] in context with path [/cms] threw exception
java.lang.IllegalStateException
	at org.apache.catalina.connector.ResponseFacade.sendError(ResponseFacade.java:433)
	at org.apache.struts2.dispatcher.Dispatcher.sendError(Dispatcher.java:771)
	at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:506)
	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:244)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.struts2.dispatcher.ActionContextCleanUp.doFilter(ActionContextCleanUp.java:102)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:244)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:244)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:244)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:550)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:380)
	at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:284)
	at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:322)
	at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1684)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:619)

很少的输出信息，在网上搜了好多，也没找到相同问题，找到一个类似的错误。

// Strust2、Freemarker
java.lang.IllegalStateException: Cannot create a session after the response  

试着按照这个错误的解决办法，竟然成功了。

解决办法：在Strust.xml文件中找到导致出错的Action配置，增加拦截：
<interceptor-ref name="createSession"/>
<interceptor-ref name="defaultStack"/>
Strust2中自带的拦截器有：<interceptor name="create-session" class="com.opensymphony.webwork.interceptor.CreateSessionInterceptor"/>
可以参考： http://struts.apache.org/2.2.1/docs/create-session-interceptor.html

还是不知道什么原因，错误报的太少了，但是总算解决了，记录一下。