java.lang.IllegalStateException: getOutputStream()

2008-06-10 02:46:59,469 [ajp-0.0.0.0-8009-2] ERROR org.apache.catalina.core.ContainerBase.[jboss.web].[localhost].[/OnRoute].[jsp] - Servlet.service() for servlet jsp threw exception
java.lang.IllegalStateException: getOutputStream() has already been called for this response
        at org.apache.catalina.connector.Response.getWriter(Response.java:604)
        at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:198)
        at com.opensymphony.module.sitemesh.filter.PageResponseWrapper$5.activateDestination(PageResponseWrapper.java:95)
        at com.opensymphony.module.sitemesh.filter.RoutablePrintWriter.getDestination(RoutablePrintWriter.java:38)
        at com.opensymphony.module.sitemesh.filter.RoutablePrintWriter.write(RoutablePrintWriter.java:144)
        at org.apache.jasper.runtime.JspWriterImpl.flushBuffer(JspWriterImpl.java:119)
        at org.apache.jasper.runtime.PageContextImpl.release(PageContextImpl.java:191)
        at org.apache.jasper.runtime.JspFactoryImpl.internalReleasePageContext(JspFactoryImpl.java:118)
        at org.apache.jasper.runtime.JspFactoryImpl.releasePageContext(JspFactoryImpl.java:77)
        at org.apache.jsp.jsp.imageSuccess_jsp._jspService(imageSuccess_jsp.java:77)
        at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
        at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:387)
        at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
        at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:687)
        at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:469)
        at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:403)
        at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:301)
        at org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1069)
        at org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:455)
        at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:279)
        at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
        at com.pb.onroute.common.web.OnRouteActionServlet.process(OnRouteActionServlet.java:111)
        at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:507)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:119)
        at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:55)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at com.pb.onroute.common.OnRouteUserDataFilter.doFilter(OnRouteUserDataFilter.java:217)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at com.infosys.j2ee.subframework.presentation.web.filter.security.SecurityFilter.doFilter(SecurityFilter.java:148)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at com.pb.onroute.common.SSOFilter.doFilter(SSOFilter.java:89)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
        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:230)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
        at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:179)
        at org.jboss.web.tomcat.service.session.ClusteredSessionValve.invoke(ClusteredSessionValve.java:87)
        at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:84)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
        at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:157)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:241)
        at org.apache.coyote.ajp.AjpProcessor.process(AjpProcessor.java:437)
        at org.apache.coyote.ajp.AjpProtocol$AjpConnectionHandler.process(AjpProtocol.java:381)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
        at java.lang.Thread.run(Thread.java:619)
2008-06-10 02:46:59,470 [ajp-0.0.0.0-8009-2] ERROR org.apache.catalina.core.ContainerBase.[jboss.web].[localhost].[/OnRoute].[action] - Servlet.service() for servlet action threw exception
java.lang.IllegalStateException: Cannot forward after response has been committed
        at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:313)
        at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:301)
        at com.infosys.j2ee.subframework.presentation.web.filter.security.SecurityFilter.handleError(SecurityFilter.java:189)
        at com.infosys.j2ee.subframework.presentation.web.filter.security.SecurityFilter.doFilter(SecurityFilter.java:168)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at com.pb.onroute.common.SSOFilter.doFilter(SSOFilter.java:89)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
        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:230)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
        at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:179)
        at org.jboss.web.tomcat.service.session.ClusteredSessionValve.invoke(ClusteredSessionValve.java:87)
        at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:84)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
        at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:157)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:241)
        at org.apache.coyote.ajp.AjpProcessor.process(AjpProcessor.java:437)
        at org.apache.coyote.ajp.AjpProtocol$AjpConnectionHandler.process(AjpProtocol.java:381)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
        at java.lang.Thread.run(Thread.java:619)
2008-06-10 02:46:59,477 [ajp-0.0.0.0-8009-2] ERROR org.apache.catalina.core.ContainerBase.[jboss.web].[localhost] - Exception Processing ErrorPage[exceptionType=java.lang.Throwable, location=/jsp/error.jsp]
java.lang.IllegalStateException
        at org.apache.coyote.Response.reset(Response.java:297)
        at org.apache.catalina.connector.Response.reset(Response.java:652)
        at org.apache.catalina.connector.Response.reset(Response.java:916)
        at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:417)
        at org.apache.catalina.core.StandardHostValve.throwable(StandardHostValve.java:271)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
        at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:157)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:241)
        at org.apache.coyote.ajp.AjpProcessor.process(AjpProcessor.java:437)
        at org.apache.coyote.ajp.AjpProtocol$AjpConnectionHandler.process(AjpProtocol.java:381)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
        at java.lang.Thread.run(Thread.java:619)



是web容器生成的servlet代码中有out.write(""),这个和JSP中调用的response.getOutputStream()产生冲突.即Servlet规范说明，不能既调用response.getOutputStream()，又调用response.getWriter(),无论先调用哪一个，在调用第二个时候应会抛出IllegalStateException，因为在jsp中，out变量实际上是通过response.getWriter得到的，程序中既用了response.getOutputStream，又用了out变量，故出现以上错误。
解决方案：在程序的最后添加：

out.clear(); 
out = pageContext.pushBody();