JavaWeb16.5【Cookie&Session：Session原理、快速入门】

 1 package com.haifei.session;
 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 javax.servlet.http.HttpSession;
 9 import java.io.IOException;
10 
11 /**
12  * session快速入门
13  */
14 @WebServlet("/SessionDemo1")
15 public class SessionDemo1 extends HttpServlet {
16     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
17         //使用session共享数据
18 
19         //1 获取session对象
20         HttpSession session = request.getSession();
21         //2 存储数据
22         session.setAttribute("msg", "hello session");
23     }
24 
25     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
26         this.doPost(request, response);
27     }
28 }

 1 package com.haifei.session;
 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 javax.servlet.http.HttpSession;
 9 import java.io.IOException;
10 
11 /**
12  * session快速入门
13  */
14 @WebServlet("/SessionDemo2")
15 public class SessionDemo2 extends HttpServlet {
16     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
17         //使用session获取数据
18 
19         //1 获取session对象
20         HttpSession session = request.getSession();
21         //2 获取数据
22         Object msg = session.getAttribute("msg");
23         System.out.println(msg);
24 
25         //一次会话，两次/多次请求间的数据共享（两者之间并没有发生资源跳转）。
26         /*
27         http://localhost:8080/day16/SessionDemo1
28         http://localhost:8080/day16/SessionDemo2
29 
30         hello session
31          */
32 
33         /*
34         重启浏览器
35         http://localhost:8080/day16/SessionDemo2
36 
37         null
38          */
39     }
40 
41     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
42         this.doPost(request, response);
43     }
44 }