Java-Servlet.service() for servlet Controller threw exception

Question

验证！
201312021936验证！

[2013-十二月-03 13:47:57][ERROR] Servlet.service() for servlet Controller 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.servlet.comm.Controller.forward(Controller.java:115)
    at com.servlet.comm.Controller.doPost(Controller.java:91)
    at com.servlet.comm.Controller.doGet(Controller.java:34)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
    at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:667)
    at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
    at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
    at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
    at java.lang.Thread.run(Thread.java:595)

Answer 1

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

"forward should be called before the response has been committed to the client (before response body output has been flushed). If the response already has been committed, this method throws an IllegalStateException. Uncommitted output in the response buffer is automatically cleared before the forward."

引自 javadoc：http://docs.oracle.com/javaee/6/api/javax/servlet/RequestDispatcher.html#forward(javax.servlet.ServletRequest, javax.servlet.ServletResponse)