websphere文件下载问题
00000031 ServletWrappe E SRVE0068E: 无法调用 servlet /test/test.jsp 的 service() 方法。抛出异常：java.lang.IllegalStateException: SRVE0199E: 已获取了输出流?
at com.ibm.ws.webcontainer.srt.SRTServletResponse.getWriter(SRTServletResponse.java:463)?
at org.apache.jasper.runtime.JspWriterImpl.initOut(JspWriterImpl.java:170)?
at org.apache.jasper.runtime.JspWriterImpl.flushBuffer(JspWriterImpl.java:163)?
at org.apache.jasper.runtime.PageContextImpl.release(PageContextImpl.java:216)?
at org.apache.jasper.runtime.JspFactoryImpl.internalReleasePageContext(JspFactoryImpl.java:149)?
at org.apache.jasper.runtime.JspFactoryImpl.releasePageContext(JspFactoryImpl.java:117)?
at com.ibm._jsp._SceneReport._jspService(_SceneReport.java:101)?
at com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:88)?
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)?
at com.ibm.ws.http.channel.inbound.impl.?
[05-10-18 15:27:23:598 CST] 00000031 ServletWrappe E SRVE0014E: 未捕捉到 service() 异常的根本原因 /taking/SceneReport.jsp：SRVE0199E: 已获取了输出流?
[05-10-18 15:27:23:618 CST] 00000031 SystemOut O doFilter 1:javax.servlet.ServletException: SRVE0199E: 已获取了输出流??
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1216)?
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1177)?
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:92)?
at com.mcm.util.tools.SessionFilter.doFilter(SessionFilter.java:195)?
at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:142)?
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:77)?
at com.mcm.util.tools.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:119)?
at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:142)?
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:77)?
at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:627)?
at com.ibm.wsspi.webcontainer.servlet.GenericServletWrapper.handleRequest(GenericServletWrapper.java:117)
at com.ibm.ws.jsp.webcontainerext.JSPExtensionServletWrapper.handleRequest(JSPExtensionServletWrapper.java:173)
at com.ibm.ws.webcontainer.servlet.CacheServletWrapper.handleRequest(CacheServletWrapper.java:80)?
at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:1752)
at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:77)?
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:466)?
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewInformation(HttpInboundLink.java:405)?
at com.ibm.ws.http.channel.inbound.impl.HttpICLReadCallback.complete(HttpICLReadCallback.java:104)?
at com.ibm.ws.tcp.channel.impl.WorkQueueManager.requestComplete(WorkQueueManager.java:555)?
at com.ibm.ws.tcp.channel.impl.WorkQueueManager.attemptIO(WorkQueueManager.java:608)?
at com.ibm.ws.tcp.channel.impl.WorkQueueManager.workerRun(WorkQueueManager.java:941)?
at com.ibm.ws.tcp.channel.impl.WorkQueueManager$Worker.run(WorkQueueManager.java:1028)?
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java(Compiled Code))
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原因：
原因是由于Servlet 规范不同造成的.?
Servlet1.2规范规定了OutputStream只能获得一次，在jsp中实际上已经通过内置对象out获得过一次，所以在程序里输出excel等文件时需要再getOutoutStream时就会报：OutputStream already obtained, WAS6里面遇上这种情况就直接报错并且不会正确执行输出，而WAS5。0只是报错但是还是允许输出。WAS6实际上对规范的实现更加严格了。?
解决方法：将进行输出的jsp改用servlet实现。因为servlet里面没有内置的out对象，所以程序执行etOutoutStream就不会出错