2015-01-06 18:23:17.160:WARN::Committed before 500 Unable to show problem report:|java.lang.IllegalStateException: STREAM||Class: org.mortbay.jetty.Response|File: Response.java|Method: getWriter|Line: 616 - org/mortbay/jetty/Response.java:616:-1
2015-01-06 18:23:17.160:WARN::/BaiDuMessageTest/message.action
java.lang.IllegalStateException: Committed
	at org.mortbay.jetty.Response.resetBuffer(Response.java:1023)
	at org.mortbay.jetty.Response.sendError(Response.java:240)
	at org.apache.struts2.dispatcher.DefaultDispatcherErrorHandler.handleErrorInDevMode(DefaultDispatcherErrorHandler.java:109)
	at org.apache.struts2.dispatcher.DefaultDispatcherErrorHandler.handleError(DefaultDispatcherErrorHandler.java:57)
	at org.apache.struts2.dispatcher.Dispatcher.sendError(Dispatcher.java:909)
	at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:576)
	at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81)
	at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
	at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:399)
	at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
	at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
	at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:766)
	at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:450)
	at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
	at org.mortbay.jetty.Server.handle(Server.java:326)
	at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
	at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:928)
	at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:549)
	at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
	at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
	at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)
	at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)

造成这个错误的原因是Response.getWriter() 和Response.getOutputStream冲突。

转：详细原因

WARN::Committed before 500 Unable to show problem report:|java.lang.IllegalStateException