After_End/MVC/target/classes/JSP/jsp_case.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="javax.servlet.ServletException" %>
<%@ page import="javax.servlet.annotation.WebServlet" %>
<%@ page import="javax.servlet.http.Cookie" %>
<%@ page import="javax.servlet.http.HttpServlet" %>
<%@ page import="javax.servlet.http.HttpServletRequest" %>
<%@ page import="javax.servlet.http.HttpServletResponse" %>
<%@ page import="java.io.IOException" %>
<%@ page import="java.net.URLDecoder" %>
<%@ page import="java.net.URLEncoder" %>
<%@ page import="java.text.SimpleDateFormat" %>
<%@ page import="java.util.Date" %>

<html>
    <head>
        <title>jsp_test</title>
    </head>

    <body>
        <%
            //设置响应的消息体的数据格式及其编码

            //1、获取所有Cookie
            Cookie[] cookies = request.getCookies();

            boolean flag = false;//标记是否访问过

            //2、遍历Cookie数组
            if (cookies != null && cookies.length > 0) {
                for (Cookie cookie : cookies) {
                    //3、获取Cookie的名称
                    String name = cookie.getName();

                    //4、判断名称是否是 lastTime
                    if ("lastTime".equals(name)) {
                        //有该Cookie，不是第一次访问 -- 取出时间
                        String value = cookie.getValue();
                        flag = true;

                        //重新设置Cookie的value
                        Date date = new Date();
                        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd  HH:mm:ss");
                        String str_date = sdf.format(date);

                        //Cookie不能有特殊字符 -- 如:空格 -- 需要转码
                        //URL编码
                        System.out.println("编码前：" + str_date);
                        str_date = URLEncoder.encode(str_date, "UTF-8");
                        System.out.println("编码后：" + str_date);

                        cookie.setValue(str_date);//更换内部数据

                        //设置Cookie的存活时间
                        cookie.setMaxAge(60 * 60 * 24 * 30);//一个月
                        response.addCookie(cookie);//会自动把name相同的Cookie替换掉

                        //URL解码
                        value = URLDecoder.decode(value, "UTF-8");
                        %>

                        <h1>欢迎回来，您上次访问的时间是：<%= value %></h1>
                        您想要的是：<input type="text">

<%
                        break;
                    }
                }

                //是第一次访问
                if (!flag) {
                    //创造cookie
                    Date date = new Date();
                    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd  HH:mm:ss");
                    String str_date = sdf.format(date);

                    //URL编码
                    System.out.println("编码前：" + str_date);
                    str_date = URLEncoder.encode(str_date, "UTF-8");
                    System.out.println("编码后：" + str_date);

                    Cookie cookie = new Cookie("lastTime", str_date);

                    //设置Cookie的存活时间
                    cookie.setMaxAge(60 * 60 * 24 * 30);//一个月
                    response.addCookie(cookie);
%>

                    <h1>您好！这是您的首次访问</h1>


                    <%
                }
            }
        %>
    </body>

</html>