这个问题如何解决?Cannot forward after response has been committed

这个问题如何解决?Cannot forward after response has been committed

做了一个应用
是在JBoss-3.2.7上的
用户自己去登陆时
一点也没问题

现在用LoadRunner去进行注册时
用了一二个用户做并发测试都会抛出异常
是在执行下面语句时出错的
this.getServletContext().getRequestDispatcher("/main.jsp").forward(req, res);

我在此语句之前已经去掉了写到后台语句
System.out.println(""); //这样的语句全注释掉了
我在server.xml里也改过最大线程数为200
如下
<Connector port="8088" address="${jboss.bind.address}"
maxThreads="200" minSpareThreads="25" maxSpareThreads="75"
enableLookups="false" redirectPort="8443" acceptCount="10" debug="0"
connectionTimeout="20000" disableUploadTimeout="true"/>
为什么还会出这样的错呢?
才一二个用户啊都出错
想想也不太可能啊

出错信息是:
2005-07-22 15:00:27,656 ERROR [org.jboss.web.localhost.Engine] StandardWrapperValve[loginservlet]: Servlet.service() for servlet loginservlet threw exception
java.lang.IllegalStateException: Cannot forward after response has been committed
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:324)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312)
at com.saintbo.servlet.sys.LoginServlet.handle(LoginServlet.java:82)
at com.saintbo.servlet.MyExtendedServlet.service(MyExtendedServlet.java:75)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:75)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.jboss.web.tomcat.security.CustomPrincipalValve.invoke(CustomPrincipalValve.java:66)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:162)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:536)

估计你的response在forward()执行前已经返回