java 下载出错

Question

各位路过的朋友，帮帮怎么解决以下问题

严重: 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:611)
 at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:198)
 at org.apache.jasper.runtime.JspWriterImpl.initOut(JspWriterImpl.java:125)
 at org.apache.jasper.runtime.JspWriterImpl.flushBuffer(JspWriterImpl.java:118)
 at org.apache.jasper.runtime.PageContextImpl.release(PageContextImpl.java:188)
 at org.apache.jasper.runtime.JspFactoryImpl.internalReleasePageContext(JspFactoryImpl.java:118)
 at org.apache.jasper.runtime.JspFactoryImpl.releasePageContext(JspFactoryImpl.java:77)
 at org.apache.jsp.error_jsp._jspService(error_jsp.java:86)
 at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
 at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:386)
 at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
 at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
 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:646)
 at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:436)
 at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374)
 at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302)
 at org.apache.struts2.dispatcher.ServletDispatcherResult.doExecute(ServletDispatcherResult.java:157)
 at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:186)
 at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:373)
 at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:277)
 at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
 at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:498)
 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 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:102)
 at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:554)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
 at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
 at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
 at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
 at java.lang.Thread.run(Thread.java:662)

Answer 1

谢谢，萌萌哒，这个问题解决了

Answer 2

回复
可否告知你的这个问题怎么解决吗

Answer 3

发生2次重定向了。。

Answer 4

at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374)
 at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302)

看起来是forward引起的，你看看在forward之前是否有向客户端输出什么东西。如果有输出，那么forward会抛出IllegalStateException的。

The forward method of the RequestDispatcher interface may be called by the calling servlet only when no output has been committed to the client. If output data exists in the response buffer that has not been committed, the content must be cleared before the target servlet’s service method is called. If the response has been committed, an IllegalStateException must be thrown.