如何通过JSP中的RequestDispatcher调用一个类

我做了一个类RedirectManager，它有一个方法doRedirect(request, response, url)，它的作用是使用RequestDispatcher方法forward()转发到指定的url（一个String参数）。我希望点击JSP页面上的链接（考虑一个现有的）RedirectManager的对象调用doRedirect(url)。如何通过JSP中的RequestDispatcher调用一个类

如何在点击链接时调用此方法？

来源

2014-10-03 Malwinder Singh

好了，一个办法做到这一点（我猜）是发送从你的链接的HTTP GET请求，这样

<%@ page language="java" contentType="text/html; charset=UTF-8" 
    pageEncoding="UTF-8"%> 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 
<html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 
</head> 
<body> 
<a href="./MyJspAction?targetUrl=page.html">click here</a> 
</body> 
</html>

这个JSP将请求发送到一个servlet

package mypackage; 

import java.io.IOException; 
import javax.servlet.ServletException; 
import javax.servlet.annotation.WebServlet; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 

/** 
* Servlet implementation class MyJspAction 
*/ 
@WebServlet("/MyJspAction") 
public class MyJspAction extends HttpServlet { 
    private static final long serialVersionUID = 1L; 
    /** 
    * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) 
    */ 
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
     String targetUrl = request.getParameter("targetUrl"); 
     new RedirectManager().doRedirect(request,response,targetUrl); 
    } 
}

那么servlet调用你的RedirectManager对象

package mypackage; 

import java.io.IOException; 

import javax.servlet.ServletException; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 

public class RedirectManager { 

    public void doRedirect(HttpServletRequest request, 
      HttpServletResponse response, String targetUrl) throws ServletException, IOException { 

     request.getRequestDispatcher(targetUrl).forward(request, response); 

    } 

}

发送请求到page.html

<html> 
Hello 
</html>

请注意forward and redirect are different things。

来源

2014-10-03 11:39:29 Leo

如何通过JSP中的RequestDispatcher调用一个类

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