Results 1 to 4 of 4
  1. 07-08-2012, 04:37 PM #1
    oszc
    oszc is offline Member
    Join Date
    Aug 2011
    Posts
    20
    Rep Power
    0

    Unhappy help with request$dispatcher problem in jsp custom tag

    hi,everyone
    I write a custom jsp tag to decide weather to display the content below, which depends on the html header property "Referer" .
    Java Code: 
    package com.zc.tag;
import java.io.IOException;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;

public class RefererDemo extends SimpleTagSupport {
	
	private String site;
	private String adPage;
	public void setSite(String site) {
		this.site = site;
	}
	public void setAdPage(String adPage) {
		this.adPage = adPage;
	}
	@Override
	public void doTag() throws JspException, IOException {
		PageContext pc = (PageContext)getJspContext();
		HttpServletRequest request = (HttpServletRequest)pc.getRequest();
		HttpServletResponse response = (HttpServletResponse)pc.getResponse();
		String refererValue = request.getHeader("Referer");
		if(refererValue==null||!refererValue.startsWith(site)){
			try {
				request.getRequestDispatcher(adPage).forward(request, response);
				throw new SkipPageException();
			} catch (ServletException e) {
				e.printStackTrace();
			}
		}
	}
}
    Java Code: 
    <%@page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="http://oszc.dyndns.info/heima" prefix="mytag" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<mytag:RefererDemo adPage="/1.html" site="http://127.0.0.1"/> 
<!-- if the adPage linked to a html file err message will be displayed -->
<!-- java.lang.IllegalStateException: getOutputStream() has already been called for this response -->

<!-- but the adPage change to "somejspfile.jsp" like below then request$dispatch works perfect-->
<!--  mytag:RefererDemo adPage="/ad.jsp" site="http://127.0.0.1"/ --> 
<html> 
  <head>
    
    <title>My JSP 'referTest1.jsp' starting page</title>

  </head>
  <body>
    test!!!
  </body>
</html>
    Java Code: 
    java.lang.IllegalStateException: getOutputStream() has already been called for this response
	at org.apache.catalina.connector.Response.getWriter(Response.java:611)
	at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:198)
	at org.apache.jasper.runtime.JspWriterImpl.initOut(JspWriterImpl.java:125)
	at org.apache.jasper.runtime.JspWriterImpl.flushBuffer(JspWriterImpl.java:118)
	at org.apache.jasper.runtime.PageContextImpl.release(PageContextImpl.java:188)
	at org.apache.jasper.runtime.JspFactoryImpl.internalReleasePageContext(JspFactoryImpl.java:118)
	at org.apache.jasper.runtime.JspFactoryImpl.releasePageContext(JspFactoryImpl.java:77)
	at org.apache.jsp.referTest1_jsp._jspService(referTest1_jsp.java:85)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:291)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602)
	at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
	at java.lang.Thread.run(Thread.java:619)
    Reply With Quote Reply With Quote
  2. 07-09-2012, 11:00 AM #2
    Tolls
    Tolls is offline Moderator
    Join Date
    Apr 2009
    Posts
    10,481
    Rep Power
    16

    Default Re: help with request$dispatcher problem in jsp custom tag

    You cannot redirect when the JSP is already being sent.
    Please do not ask for code as refusal often offends.
    Reply With Quote Reply With Quote
  3. 07-09-2012, 11:31 AM #3
    oszc
    oszc is offline Member
    Join Date
    Aug 2011
    Posts
    20
    Rep Power
    0

    Default Re: help with request$dispatcher problem in jsp custom tag

    Quote Originally Posted by Tolls View Post
    You cannot redirect when the JSP is already being sent.
    hi,Tolls

    As i describe in the html annotation, when redirect to a jsp file there is no error , But the exception was thrown when i redirect to a html file,
    I cannot figure out what's the different between jsp and html files when the container execute redirect code ?
    Last edited by oszc; 07-09-2012 at 11:35 AM.
    Reply With Quote Reply With Quote
  4. 07-09-2012, 12:28 PM #4
    Tolls
    Tolls is offline Moderator
    Join Date
    Apr 2009
    Posts
    10,481
    Rep Power
    16

    Default Re: help with request$dispatcher problem in jsp custom tag

    Oh sorry, I thought that was a redirect, not a forward.
    Please do not ask for code as refusal often offends.
    Reply With Quote Reply With Quote
« Dynamically including JSP page | Rewriting EL expressions in a loop »

Similar Threads

  1. Dispatcher
    By abhinav_sharma in forum New To Java
    Replies: 2
    Last Post: 04-24-2012, 05:41 PM
  2. Cookies and request.getAttribute() / request.setAttribute() question
    By Walter in forum New To Java
    Replies: 2
    Last Post: 03-29-2012, 10:32 AM
  3. Get Request Problem In Android
    By Ya2 in forum Android
    Replies: 7
    Last Post: 07-26-2011, 08:25 PM
  4. problem with ServletRequest request.getInputStream
    By bbq in forum Java Servlet
    Replies: 2
    Last Post: 02-27-2011, 10:50 AM
  5. The Struts dispatcher cannot be found
    By Md Saim in forum Web Frameworks
    Replies: 0
    Last Post: 12-16-2008, 06:37 AM

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Forum Rules