javaweb学习总结(十一)——使用Cookie进行会话管理

 1 package gac.xdp.cookie;
 2 
 3 import java.io.IOException;
 4 import java.io.PrintWriter;
 5 import java.util.Date;
 6 import javax.servlet.ServletException;
 7 import javax.servlet.http.Cookie;
 8 import javax.servlet.http.HttpServlet;
 9 import javax.servlet.http.HttpServletRequest;
10 import javax.servlet.http.HttpServletResponse;
11 
12 /**
13  * @author gacl
14  * cookie实例：获取用户上一次访问的时间
15  */
16 public class CookieDemo01 extends HttpServlet {
17 
18     public void doGet(HttpServletRequest request, HttpServletResponse response)
19             throws ServletException, IOException {
20         //设置服务器端以UTF-8编码进行输出
21         response.setCharacterEncoding("UTF-8");
22         //设置浏览器以UTF-8编码进行接收,解决中文乱码问题
23         response.setContentType("text/html;charset=UTF-8");
24         PrintWriter out = response.getWriter();
25         //获取浏览器访问访问服务器时传递过来的cookie数组
26         Cookie[] cookies = request.getCookies();
27         //如果用户是第一次访问，那么得到的cookies将是null
28         if (cookies!=null) {
29             out.write("您上次访问的时间是：");
30             for (int i = 0; i < cookies.length; i++) {
31                 Cookie cookie = cookies[i];
32                 if (cookie.getName().equals("lastAccessTime")) {
33                     Long lastAccessTime =Long.parseLong(cookie.getValue());
34                     Date date = new Date(lastAccessTime);
35                     out.write(date.toLocaleString());
36                 }
37             }
38         }else {
39             out.write("这是您第一次访问本站！");
40         }
41         
42         //用户访问过之后重新设置用户的访问时间，存储到cookie中，然后发送到客户端浏览器
43         Cookie cookie = new Cookie("lastAccessTime", System.currentTimeMillis()+"");//创建一个cookie，cookie的名字是lastAccessTime
44         //将cookie对象添加到response对象中，这样服务器在输出response对象中的内容时就会把cookie也输出到客户端浏览器
45         response.addCookie(cookie);
46     }
47 
48     public void doPost(HttpServletRequest request, HttpServletResponse response)
49             throws ServletException, IOException {
50         doGet(request, response);
51     }
52 
53 }

1 //用户访问过之后重新设置用户的访问时间，存储到cookie中，然后发送到客户端浏览器
2 Cookie cookie = new Cookie("lastAccessTime", System.currentTimeMillis()+"");//创建一个cookie，cookie的名字是lastAccessTime
3 //设置Cookie的有效期为1天
4 cookie.setMaxAge(24*60*60);
5 //将cookie对象添加到response对象中，这样服务器在输出response对象中的内容时就会把cookie也输出到客户端浏览器
6 response.addCookie(cookie);

 1 package gac.xdp.cookie;
 2 
 3 import java.io.IOException;
 4 
 5 import javax.servlet.ServletException;
 6 import javax.servlet.http.Cookie;
 7 import javax.servlet.http.HttpServlet;
 8 import javax.servlet.http.HttpServletRequest;
 9 import javax.servlet.http.HttpServletResponse;
10 
11 /**
12  * @author gacl
13  * 删除cookie
14  */
15 public class CookieDemo02 extends HttpServlet {
16 
17     public void doGet(HttpServletRequest request, HttpServletResponse response)
18             throws ServletException, IOException {
19         //创建一个名字为lastAccessTime的cookie
20         Cookie cookie = new Cookie("lastAccessTime", System.currentTimeMillis()+"");
21         //将cookie的有效期设置为0，命令浏览器删除该cookie
22         cookie.setMaxAge(0);
23         response.addCookie(cookie);
24     }
25 
26     public void doPost(HttpServletRequest request, HttpServletResponse response)
27             throws ServletException, IOException {
28         doGet(request, response);
29     }
30 }

1 Cookie cookie = new Cookie("userName", URLEncoder.encode("孤傲苍狼", "UTF-8"));
2 response.addCookie(cookie);

1 URLDecoder.decode(cookies[i].getValue(), "UTF-8")