cookie的实例

使得Cookie简化用户登陆，要求如下：

1、用户第一次登陆时需要输入用户名和密码

2、当登陆成功后，在Cookie中保存用户的登陆信息

3、设置Cookie有效期为5分钟

4、在有效期内用户再次登陆时，直接显示用户名

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>login</title>

</head>
<body>

<%
    Cookie cookie[] = request.getCookies();
    String name ="";
    if(cookie!=null){
    
        for(int i=0;i<cookie.length;i++){
            if(cookie[i].getName().equals("username")){
                name = cookie[i].getValue();
                
            }
        }
    }

 %>

 
<form action="checklogin.jsp" method="post">
    <table>
        <tr>
            <td>用户名：</td>
            <td><input type="text"  id="username" name="username" value="<%=name %>" /></td>
        </tr>
        <tr>
            <td>密码：</td>
            <td><input type="text" name="password" /></td>
        </tr>
        <tr>
            <td></td>
            <td><input type="submit" value="登陆" /></td>
        </tr>
    
    </table>


</form>


</body>
</html>

checklogin.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>login</title>
</head>
<body>
    <%
        String username = request.getParameter("username");
        String pwd = request.getParameter("password");
        Cookie cookie = new Cookie("username",username);
        //jsp要把封装好的cookie传递给客户端
        response.addCookie(cookie);
        cookie.setMaxAge(180000);
    
     %>
</body>
</html>