保存状态的两种方式

 1 package com.bjsxt.cookie;
 2 
 3 import java.io.IOException;
 4 import java.net.URLEncoder;
 5 
 6 import javax.servlet.ServletException;
 7 import javax.servlet.annotation.WebServlet;
 8 import javax.servlet.http.Cookie;
 9 import javax.servlet.http.HttpServlet;
10 import javax.servlet.http.HttpServletRequest;
11 import javax.servlet.http.HttpServletResponse;
12 
13 /**
14  * Servlet implementation class TestSetCookie
15  */
16 @WebServlet("/TestSetCookie")
17 public class TestSetCookie extends HttpServlet {
18 
19     @Override
20     protected void service(HttpServletRequest req, HttpServletResponse resp)
21             throws ServletException, IOException {
22     System.out.println("TestSetCookie.service()");
23     //创建cookie
24     Cookie cookie01=new Cookie("vivo","vivox5");
25     Cookie cookie02=new Cookie("vivo","vivox6");
26     Cookie cookie03=new Cookie("vivo","vivox7");
27     Cookie cookie04=new Cookie("vivo","vivox21");
28     //设置中文编码cookie
29     Cookie cookie05=new Cookie("vivo",URLEncoder.encode("步步高五","utf-8"));
30     //设置cookie信息的有效期,setmaxage是以秒为单位
31     cookie03.setMaxAge(3*24*3600);
32     cookie04.setMaxAge(3*24*3600);
33     //设置cookie的访问路径
34     cookie01.setPath(req.getContextPath()+"/abc");
35     
36     //发送给客户端
37     resp.addCookie(cookie01);
38     resp.addCookie(cookie02);
39     resp.addCookie(cookie03);
40     resp.addCookie(cookie04);
41     resp.addCookie(cookie05);
42     }
43     
44 
45 }

 1 package com.bjsxt.cookie;
 2 
 3 import java.io.IOException;
 4 import java.net.URLDecoder;
 5 
 6 import javax.servlet.ServletException;
 7 import javax.servlet.annotation.WebServlet;
 8 import javax.servlet.http.Cookie;
 9 import javax.servlet.http.HttpServlet;
10 import javax.servlet.http.HttpServletRequest;
11 import javax.servlet.http.HttpServletResponse;
12 
13 /**
14  * Servlet implementation class TestGetCookie
15  */
16 @WebServlet("/TestGetCookie")
17 public class TestGetCookie extends HttpServlet {
18 
19     @Override
20     protected void service(HttpServletRequest req, HttpServletResponse resp)
21             throws ServletException, IOException {
22         System.out.println("TestGetCookie.service()");
23         //获取cookie--获取请求头里的cookie（从浏览器获取）
24         Cookie[] cookies=req.getCookies();
25         //获取cookie的名称和值
26         for(int i=0;i<cookies.length;i++){
27             System.out.println("cookie:"+cookies[i].getName()+":"+ URLDecoder.decode(cookies[i].getValue(),"utf-8"));
28         }
29     }
30 
31 }

session

 1 package com.bjsxt.session;
 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 import javax.servlet.http.HttpSession;
11 /**
12  * session:将http状态信息保存在服务器端的技术
13  * seesion是客户端和服务器之间的一次会话
14  *   会话-开始：当用户第一访问服务器时候就开始了
15  *         结束：客户端--关闭浏览器（清除cookie）
16  *           服务器--A:超过有效期 在tomcat中web.xml中配置   <session-config>
17                                                     <session-timeout>30</session-timeout>
18                                                  </session-config>
19  *                   B:在本项目中web.xml配置session-config
20  *                  C:设置session的最大不活动周期
21  *                  D:服务器关闭
22  *   
23  *
24  * cookie:不安全，效率低，容量小，但是不能舍弃这门技术，因为session的跟踪机制需要cookie来保存JSESSIONID
25  */
26 @WebServlet("/HelloSession")
27 public class HelloSession extends HttpServlet {
28 
29     @Override
30     protected void service(HttpServletRequest req, HttpServletResponse resp)
31             throws ServletException, IOException {
32         System.out.println("HelloSession.service()");
33         
34         //获取session
35         HttpSession hs = req.getSession();
36         
37         //设置sesssion的最大不活动周期
38         //hs.setMaxInactiveInterval(10);
39         
40         //强制sesssion失效
41         //hs.setMaxInactiveInterval(0);
42         //hs.invalidate();
43         
44         //获取sessionid
45         String hsid = hs.getId();
46         System.out.println("HelloSession.service()sessionid:"+hsid);
47         
48     }
49 
50     
51 }