关于 ： Cannot forward after response has been committed


Test.jsp 页面：<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ taglib uri="http://wish.jsp.tag" prefix="abc"%>
<html>
  <head>
    <title>My JSP 'test.jsp' starting page</title>
    <meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">    
 </head>
  
  <body>
 
    <abc:test url="test.jsp"/>
    dsgdfgdfgdfg <!-- 测试数据 -->
    
  </body>
</html>
index.jsp 页面:<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<html>
  <head>
    <title>My JSP 'index.jsp' starting page</title>
    <meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">    
 </head>
  
  <body>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
  <table width="909" border="1" cellpadding="0" cellspacing="0">
  <tr>
    <td height="181" colspan="2" valign="top">udydhehdydhydhydh</td>
  </tr> <!-- 测试数据 -->
  <tr>
    <td width="247" height="421" valign="top"></td>
    <td width="662" valign="top">
    <a href="MyJsp.jsp">asd</a> 
    <c:if test="${!(empty requestScope.url)}"><!--  判断是否为空-->dfsaf
    <jsp:include page="${requestScope.url}" flush="true"></jsp:include> 
    
    <!-- 导入相关页面-->
    </c:if>
  </td>
 </tr>
</table>
  </body>
</html>
助手类:package myTags;import java.io.IOException;
import java.io.PrintWriter;import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpSession;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.BodyContent;
import javax.servlet.jsp.tagext.TagSupport;public class MyTag extends TagSupport {

private String url;

public String getUrl() {
return url;
}

public void setUrl(String url) {
this.url = url;
}
public int doStartTag()
    throws JspException{

return super.doStartTag();
}
public int doEndTag()throws JspException{ ServletResponse response = pageContext.getResponse();
ServletRequest request = pageContext.getRequest();
request.setAttribute("url", this.url);
try {
request.getRequestDispatcher("index.jsp").forward(request, response);

} catch (ServletException e) {

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

e.printStackTrace();
}
return super.doEndTag();
}


}tld文件:<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.1//EN" "http://java.sun.com/j2ee/dtds/web-jsptaglibrary_1_1.dtd">
<taglib>
  <tlibversion>1.0</tlibversion>
  <jspversion>1.1</jspversion>
  <shortname>mytag</shortname>
  <uri>http://wish.jsp.tag</uri>
  <tag>
  <name>test</name>
  <tagclass>myTags.MyTag</tagclass>
  <bodycontent>empty</bodycontent>
  <attribute>
   <name>url</name><!-- url属性用于保存要加载的页面 -->
   <required>true</required>
   <rtexprvalue>true</rtexprvalue>
  </attribute>
  </tag>
</taglib>
意思是如果访问了test.jsp页面  就会加载我定义的标签 然后跳转到index.jsp页面 index.jsp页面会把test页面的内容加载进来程序运行起来是正常的 可是每次运行的时候都会出现异常:Caused by: java.lang.IllegalStateException: Cannot forward after response has been committed请问怎样解决啊 ！是不是 这样的逻辑本来就是不对的！