Cookie简单实例

Cookie简单实例

1、创建CookieServlet

 1 package com.servlet.study;
 2 
 3 import java.io.IOException;
 4 import java.io.PrintWriter;
 5 
 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 @WebServlet("/cookieServlet.do")
12 public class CookieServlet extends HttpServlet {
13     public void doGet(HttpServletRequest request, HttpServletResponse response)
14             throws ServletException, IOException {
15         //设置服务器端以UTF-8编码进行输出
16         response.setCharacterEncoding("UTF-8");
17         //设置浏览器以UTF-8编码进行接收，解决中文乱码问题
18         response.setContentType("text/html;charset = UTF-8");
19         PrintWriter out = response.getWriter();
20         
21         //获取cookie
22         String username = "";
23         String check = "";
24         Cookie[] cookies = request.getCookies();
25         for(int i = 0; cookies != null && i < cookies.length; i++){
26             Cookie c = cookies[i];
27             if("username".equals(c.getName())){
28                 username = c.getValue();
29                 check = "checked = 'checked'";
30                 break;
31             }
32         }
33         
34         //登录页面
35         out.write("<form action = '" + request.getContextPath() + "/loginCookieServlet.do' method = 'post'>");
36         out.write("用户名：<input type = 'text' name = 'username' value = '" + username + "'><br />");
37         out.write("密码：<input type = 'password' name = 'password' value = ''><br />");
38         out.write("记住用户名：<input type = 'checkbox' name = 'remember'" + check + "'><br />");
39         out.write("<input type = 'submit' name = 'submit' value = '登录'><br />");
40     }
41     public void doPost(HttpServletRequest request, HttpServletResponse response)
42             throws ServletException, IOException {
43         doGet(request, response);
44     }
45 }

2、创建LoginCookieServlet

 1 package com.servlet.study;
 2 
 3 import java.io.IOException;
 4 import java.io.PrintWriter;
 5 
 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 @WebServlet("/loginCookieServlet.do")
13 public class LoginCookieServlet extends HttpServlet {
14     public void doGet(HttpServletRequest request, HttpServletResponse response)
15             throws ServletException, IOException {
16         String username = request.getParameter("username");
17         String remember = request.getParameter("remember");
18         response.setCharacterEncoding("UTF-8");
19         response.setContentType("text/html;charset = UTF-8");
20         PrintWriter out = response.getWriter();
21         
22         //创建一个新的Cookie
23         Cookie cookie = new Cookie("username", username);
24         cookie.setPath(request.getContextPath());
25         if(remember != null){
26             //如果选择了记住用户名，则设置Cookie的有效期为一个不为0的整数
27             cookie.setMaxAge(Integer.MAX_VALUE);
28         }else{
29             //否则则把有效期设置为0，即命令浏览器删除该cookie
30             cookie.setMaxAge(0);
31         }
32         //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也输出到客户端服务器
33         response.addCookie(cookie);
34         out.write("登录成功！");
35     }
36 
37     public void doPost(HttpServletRequest request, HttpServletResponse response)
38             throws ServletException, IOException {
39         doGet(request, response);
40     }
41 }

3、访问，结果