java.lang.IllegalStateException: Cannot forward after response has been committed

今天在测试的时候出现了这样的错误：

2010-10-12 21:07:17 org.apache.catalina.core.StandardWrapperValve invoke

严重: Servlet.service() for servlet DangAnServlet 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.yin.dangan.servlet.DangAnServlet.doGet(DangAnServlet.java:433)

at com.yin.dangan.servlet.DangAnServlet.doPost(DangAnServlet.java:534)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)

at com.yin.dangan.filter.EncodingFilter.doFilter(EncodingFilter.java:24)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)

at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:873)

at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)

at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)

at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)

at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)

at java.lang.Thread.run(Thread.java:619)

在网上查了一下，百度给的提示是在Servlet中的request.getRequestDispatcher("/error.jsp").forward(request, response);的逻辑有问题，然后仔细检查了一下相应的Servlet中的相应的方法，看看了，果然是自己设计的逻辑出现了点问题~以后要注意在Servlet中用到request.getRequestDispatcher("/error.jsp").forward(request, response);时一定要if {} else {} 写完整，还有就是在逻辑上不要冲突！仔细！

最后，很高兴遇到这个问题！嘿嘿……以后不会再犯了！嘿嘿……