JSP改造Cookie案例以及Session的快速入门
<%@ page import="java.util.Date" %>
<%@ page import="java.text.SimpleDateFormat" %>
<%@ page import="java.net.URLEncoder" %>
<%@ page import="java.net.URLDecoder" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>itcast</title>
</head>
<body>
<%
//1..获取所有的Cookie
Cookie[] cookies = request.getCookies();
boolean flag = false;//没有cookie为lastTime
//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
flag = true;//有lastTime的cookie
//设置Cookie的value
//获取当前时间的字符串，重新设置Cookie的值，重新发送cookie
Date date = new Date();
SimpleDateFormat format = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss");//更改为中国格式的时间
String str_date = format.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.setValue(str_date);
//设置cookie存活时间
cookie.setMaxAge(60 * 60 * 24 * 30);//一个月
response.addCookie(cookie);//发送cookie
//响应数据
//获取cookie的value，时间
String value = cookie.getValue();
System.out.println("解码前："+value);
//URL解码
value = URLDecoder.decode(value, "utf-8");
System.out.println("解码后："+value);
%>
<h1>欢迎回来，您上次访问时间为：<%=value%>></h1>
<%
//找到直接停止
break;
}
}
}
if (cookies == null || cookies.length == 0 || flag == false ){
//没有，第一次访问
//设置Cookie的value
//获取当前时间的字符串，重新设置Cookie的值，重新发送cookie
Date date = new Date();
SimpleDateFormat format = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss");//更改为中国格式的时间
String str_date = format.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存活时间
cookie.setMaxAge(60 * 60 * 24 * 30);//一个月
response.addCookie(cookie);//发送cookie
%>
<h1>您好，欢迎您首次访问</h1>
<%
}
%>
</body>
</html>
Session的快速入门
概念：服务器端会话技术，在一次会话的多次请求间共享数据，将数据保存在服务器端的对象中，HttpSession
快速入门：
1.获取Session对象
HttpSession session = request.getSession();
2.使用HttpSession对象:
Object getAttribute(String name)
void setAttribute(String name,Object value)
void removeAttribute(String name)
session存储数据：
@WebServlet(name = "SessionDemo1", value = "/SessionDemo1")
public class SessionDemo1 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//使用Session共享数据
//1.获取session
HttpSession session = request.getSession();
//2.存储数据
session.setAttribute("msg", "hello session");
}
}
session获取数据
@WebServlet(name = "SessionDemo2", value = "/SessionDemo2")
public class SessionDemo2 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//使用Session共享数据
//1.获取session
HttpSession session = request.getSession();
//2.获取数据
Object msg = session.getAttribute("msg");
System.out.println(msg);
}
}
标签：cookie,name,Session,request,value,session,Cookie,date,JSP From： https://www.cnblogs.com/qihaokuan/p/16974300.html