2015-08-09 25 views
2

我想學習abt servlets。 當我調用forward()時,我得到一個IllegalStateException。該錯誤發生在LoginBean.do if塊在我呼叫的地方。當我向前撥號時得到一個IllegalStateException()

 process(request,response); 
} 

private void process(HttpServletRequest request, HttpServletResponse response) { 
    // TODO Auto-generated method stub 
    String uri = request.getRequestURI(); 
    RequestDispatcher rd = null; 
    CAppModel model = new CAppModel(); 

    System.out.println("Inside process()"); 
    try{ 
    if(uri.contains("/Login")) 
    { 
     System.out.println("Inside Login.do"); 
     rd = request.getRequestDispatcher("Login.jsp"); 
     rd.forward(request,response); 
    } 

    if(uri.contains("/Register.do")) 
    { 
     System.out.println("inside Register.do"); 
    } 

    if(uri.contains("/LoginBean.do")) 
    { 

     System.out.println("Inside LoginBean.do"); 
     LoginBean lb = (LoginBean)request.getAttribute("login"); 
     System.out.println("toString(): "+lb.toString()); 
     String result = model.authenticate(lb); 
     System.out.println("CS: result of auth "+result); 

     if(result.equals("Success")) 
     { 
      System.out.println("Inside if Success of loginbean"); 
      HttpSession session = request.getSession(true); 
      session.setAttribute("user", lb.getEmail()); 
      rd = request.getRequestDispatcher("Menu.jsp"); 
      rd.forward(request, response); 

     } 
     else 
     { 
      System.out.println("failed auth "+result); 
      request.setAttribute("errorMsg", result); 
      rd = request.getRequestDispatcher("Login.jsp");    
      rd.forward(request,response); 
     } 


    } 
    } 
    catch(Exception e) 
    { 
     e.printStackTrace(); 
    } 
} 

/** 
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) 
*/ 
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
    // TODO Auto-generated method stub 
    process(request,response); 
} 

}

我正在以下錯誤

java.lang.IllegalStateException: Cannot forward after response has been committed 
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:328) 
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:318) 
at com.aditya.CApp.ControllerServlet.process(ControllerServlet.java:69) 
at com.aditya.CApp.ControllerServlet.doGet(ControllerServlet.java:31) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291) 
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) 
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) 
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) 
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) 
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:721) 
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:466) 
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:391) 
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:318) 
at org.apache.jasper.runtime.PageContextImpl.doForward(PageContextImpl.java:741) 
at org.apache.jasper.runtime.PageContextImpl.forward(PageContextImpl.java:711) 
at org.apache.jsp.LoginInt_jsp._jspService(LoginInt_jsp.java:104) 
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438) 
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396) 
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291) 
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) 
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) 
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) 
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) 
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219) 
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106) 
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) 
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142) 
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) 
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:617) 
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) 
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518) 
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091) 
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668) 
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1527) 
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1484) 
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) 
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) 
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) 
at java.lang.Thread.run(Unknown Source) 

回答

1

含有/LoginBean.do請求將觸發2如果要調用的第二向前後導致錯誤引起2個向前塊。雖然你可以重新安排如果語句爲

if (uri.contains("/LoginBean.do")) { 
    ... 
else if (uri.contains("/LoginBean")) { 
    ... 

通常它更簡單地使用單個servlet每塊如果功能塊。

+0

謝謝Reimeus。我在第一個條件中添加了.do。該例外停止appering。 –

0

你必須在return;之後轉發。否則下面的代碼也會執行......在你的情況下,包含/ Login和/LoginBean.do的條件

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