JavaWeb中的请求转发和重定向

Posted 2020-10-31 爱生活的Mr.Yao

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请求转发：forward(); 重定向：sendRedirect()

来看具体实例：

在html页面写两个a链接请求,这个就是get请求了，然后建立与请求对应的servlet,页面代码如下所示：

 1 <!DOCTYPE html>
 2 <html>
 3 <head>
 4 <meta charset="UTF-8">
 5 <title>请求转发实例</title>
 6 </head>
 7 <body>
 8 <h2 style="text-align: center;">Forward测试页面</h2>
 9 <a href="fowardServlet">foward请求</a>
10 <br/></br/>
11 <a href="sendServlet">send重定向</a>
12 </body>
13 </html>

然后建立请求转发ForWardServlet,并且在web.xml中配置，这个就不说了

 1 package com.servlet;
 2 
 3 import java.io.IOException;
 4 
 5 import javax.servlet.RequestDispatcher;
 6 import javax.servlet.ServletException;
 7 import javax.servlet.http.HttpServlet;
 8 import javax.servlet.http.HttpServletRequest;
 9 import javax.servlet.http.HttpServletResponse;
10 
11 public class ForwardServlet extends HttpServlet {
12     private static final long serialVersionUID = 1L;
13 
14     protected void doGet(HttpServletRequest request, HttpServletResponse response)
15             throws ServletException, IOException {
16         request.setAttribute("forward_name", "abcde");
17         System.out.println("请求转发获取的属性:" + request.getAttribute("forward_name"));
18         System.out.println("ForwardServlet 的 doGet()方法");
19         // 转发请求
20         String path = "testServlet";
21         RequestDispatcher requestDispatcher = request.getRequestDispatcher("/" + path);
22         requestDispatcher.forward(request, response);
23     }
24 
25 }

再建立请求重定向SendServlet,并且在web.xml中配置，这个也就不说了

 1 package com.servlet;
 2 
 3 import java.io.IOException;
 4 
 5 import javax.servlet.ServletException;
 6 import javax.servlet.annotation.WebServlet;
 7 import javax.servlet.http.HttpServlet;
 8 import javax.servlet.http.HttpServletRequest;
 9 import javax.servlet.http.HttpServletResponse;
10 
11 @WebServlet(name = "sendServlet", urlPatterns = "/sendServlet")
12 public class SendServlet extends HttpServlet {
13     private static final long serialVersionUID = 1L;
14 
15     protected void doGet(HttpServletRequest request, HttpServletResponse response)
16             throws ServletException, IOException {
17         request.setAttribute("send_name", "abcde");
18         System.out.println("重定向获取的属性:" + request.getAttribute("send_name"));
19         System.out.println("SendServlet 的doGet 方法");
20         String path = "testServlet";
21         response.sendRedirect(path);
22 
23     }
24 
25 }

然后建立path中所提到的 TestServlet

 1 package com.servlet;
 2 
 3 import java.io.IOException;
 4 
 5 import javax.servlet.ServletException;
 6 import javax.servlet.annotation.WebServlet;
 7 import javax.servlet.http.HttpServlet;
 8 import javax.servlet.http.HttpServletRequest;
 9 import javax.servlet.http.HttpServletResponse;
10 
11 @WebServlet("/testServlet")
12 public class TestServlet extends HttpServlet {
13     private static final long serialVersionUID = 1L;
14 
15     protected void doGet(HttpServletRequest request, HttpServletResponse response)
16             throws ServletException, IOException {
17         // TODO Auto-generated method stub
18         System.out.println("TestServlet 的 doGet 方法");
19 
20         System.out.println("测试请求转发获取的属性:" + request.getAttribute("forward_name"));
21 
22         System.out.println("测试重定向获取的属性:" + request.getAttribute("send_name"));
23     }
24 
25 }