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Cookie与Session用法

分类: IT文章 • 2022-03-30 18:38:51

Cookie与Session用法

以下是Cookie的完整实例

Cookie与Session用法

MyEclipse新建web Project工程，建两个jsp文件，如下

1、login.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    
<%
    request.setCharacterEncoding("UTF-8");
    response.setCharacterEncoding("UTF-8");
    if("POST".equals(request.getMethod())){
        Cookie usernameCookie=new Cookie("username",request.getParameter("username"));//新建名为username的Cookie
        Cookie visittimesCookie=new Cookie("visitTimes","0");    //新建Cookie
        response.addCookie(usernameCookie);//添加到response中
        response.addCookie(visittimesCookie);//response会将Cookie发送给客户端
        
        response.sendRedirect(request.getContextPath()+"/cookie.jsp");//显示Cookie页面
        return;
    }
    
 %>
    
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>请先登录</title>
<link rel="stylesheet" type="text/css" href="css/style.css">
</head>
<body>
<div align="center" style="margin:10px; ">
    <fieldset>
        <legend>登录</legend>
        <form action="login.jsp" method="post">
            <table>

                <tr>
                    <td>帐号：</td>
                    <td>
                        <input type="text" name="username" style="200px; ">
                    </td>
                </tr>
                <tr>
                    <td>密码：</td>
                    <td>
                        <input type="password" name="password" style="200px; ">
                    </td>
                </tr>
                <tr>
                    <td>
                    </td>
                    <td>
                        <input type="submit" value=" 登  录 " class="button">
                    </td>
                </tr>
            </table>
        </form>
    </fieldset>
</div>

</body>
</html>

2、cookie.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8" errorPage="login.jsp" %>
    
<%
    request.setCharacterEncoding("UTF-8");
    String username="";    //用户名
    int visitTimes=0;    //访问次数
    
    Cookie[] cookies=request.getCookies();//所有的Cookie
    for(int i=0;i<cookies.length;i++){
        Cookie cookie=cookies[i];    //第i个Cookie
        if("username".equals(cookie.getName())){
            username=cookie.getValue();
        }
        else if("visitTimes".equals(cookie.getName())){
            visitTimes=Integer.parseInt(cookie.getValue());
        }    
    }
    if(username==null||username.trim().equals("")){
        throw new Exception("还没登陆，请先登录");
    }
    
    Cookie visitTimesCookie=new Cookie("visitTimes",Integer.toString(++visitTimes));
    response.addCookie(visitTimesCookie);//覆盖名为visitTimes的Cookie
    
 %>    
    
<!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>Insert title here</title>
</head>
<body>
    <div align="center" style="margin:10px;">
        <fieldset>
            <legend>登录信息</legend>
            <form action="login.jsp" method="post">
                <table>
                    <tr>
                        <td>你的账号：</td>
                        <td><%=username %></td>
                    </tr>
                    <tr>
                        <td>登陆次数：</td>
                        <td><%=visitTimes %></td>
                    </tr>
                    <tr>
                        <td></td>
                        <td>
                            <input type="button" value="刷新" onclick="location='<%= request.getRequestURI() %>?ts='+new Date().getTime();" class="button">
                        </td>
                    </tr>
                </table>
            </form>
        </fieldset>
    </div>
</body>
</html>

效果：

Cookie与Session用法

 随便输入账号和密码，点击登录

Cookie与Session用法

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