JavaWeb15.2【response：Response对象功能、案例-重定向、绝对路径相对路径】

 

 

 

 

 

 

 1 package com.haifei.servlet;
 2 
 3 import javax.servlet.ServletException;
 4 import javax.servlet.annotation.WebServlet;
 5 import javax.servlet.http.HttpServlet;
 6 import javax.servlet.http.HttpServletRequest;
 7 import javax.servlet.http.HttpServletResponse;
 8 import java.io.IOException;
 9 
10 /**
11  * Response对象案例-重定向
12  */
13 @WebServlet("/responseDemo1")
14 public class ResponseDemo1 extends HttpServlet {
15     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
16         System.out.println("demo1被访问了。。。");
17 
18         //访问/responseDemo1资源，会自动跳转到/responseDemo2资源
19         /*//1 设置状态码为302
20         response.setStatus(302);
21         //2.设置响应头location
22         response.setHeader("location", "/day15/responseDemo2");*/
23         /*
24         http://localhost:8080/day15/responseDemo1
25 
26         demo1被访问了。。。
27         demo2被访问了。。。
28          */
29 
30         request.setAttribute("msg", "response"); //存值
31 
32 //        //有一种简单的重定向方法，可以实现上述功能
33 //        response.sendRedirect("/day15/responseDemo2");
34 ////        response.sendRedirect("http://www.bilibili.com"); //重定向可以访问其他站点(服务器)的资源
35 
36         //此外，"/day15/responseDemo2"不方便，虚拟目录可能更改频繁，且容易写错虚拟目录
37         //动态获取虚拟目录
38         String contextPath = request.getContextPath();
39         response.sendRedirect( contextPath + "/responseDemo2");
40     }
41 
42     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
43         this.doPost(request, response);
44     }
45 }
 1 package com.haifei.servlet;
 2 
 3 import javax.servlet.ServletException;
 4 import javax.servlet.annotation.WebServlet;
 5 import javax.servlet.http.HttpServlet;
 6 import javax.servlet.http.HttpServletRequest;
 7 import javax.servlet.http.HttpServletResponse;
 8 import java.io.IOException;
 9 
10 @WebServlet("/responseDemo2")
11 public class ResponseDemo2 extends HttpServlet {
12     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
13         System.out.println("demo2被访问了。。。");
14 
15         /*Object msg = request.getAttribute("msg");//取值
16         System.out.println(msg); //null --> 获取不到数据*/
17     }
18 
19     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
20         this.doPost(request, response);
21     }
22 }

 

 

 

 

 

 

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>Title</title>
 6 </head>
 7 <body>
 8     <h1>相对路径规则：找到当前资源和目标资源之间的相对位置关系</h1>
 9     <P>
10         当前资源:
11         http://localhost:8080/day15/location.html
12     </P>
13     <P>
14         目标资源:
15         http://localhost:8080/day15/responseDemo2
16     </P>
17     <a href="./responseDemo2">responseDemo2</a>  <!--相对路径中./表示当前位置，且./可以省略-->
18     <a href="responseDemo2">responseDemo2</a>  <!--相对路径中./表示当前位置，且./可以省略-->
19 
20 
21     <h1>绝对路径规则：判断定义的路径是给谁用的？即判断请求将来从哪儿发出</h1>
22     <a href="/day15/responseDemo2"> <!--绝对路径给客户端浏览器使用：需要加虚拟目录(项目的访问路径)-->
23         responseDemo2
24     </a>
25 </body>
26 </html>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <h1>找到当前资源和目标资源之间的相对位置关系</h1>
    <P>
        当前资源:
        http://localhost:8080/day15/htmls/location2.html
    </P>
    <P>
        目标资源:
        http://localhost:8080/day15/responseDemo2
    </P>

    <a href="../responseDemo2">responseDemo2</a>  <!--相对路径中../表示后退一级目录，且../不可省略-->
</body>
</html>
 1 package com.haifei.servlet;
 2 
 3 import javax.servlet.ServletException;
 4 import javax.servlet.annotation.WebServlet;
 5 import javax.servlet.http.HttpServlet;
 6 import javax.servlet.http.HttpServletRequest;
 7 import javax.servlet.http.HttpServletResponse;
 8 import java.io.IOException;
 9 
10 @WebServlet("/responseDemo3")
11 public class ResponseDemo3 extends HttpServlet {
12     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
13         //绝对路径举例
14 
15         //转发
16         request.getRequestDispatcher("/responseDemo2").forward(request, response); //绝对路径给服务器使用：不需要加虚拟目录
17         /*
18         http://localhost:8080/day15/responseDemo3
19 
20         demo2被访问了。。。
21          */
22     }
23 
24     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
25         this.doPost(request, response);
26     }
27 }

 

posted @ 2021-07-01 17:20  yub4by  阅读(81)  评论(0)  编辑  收藏  举报