Servlet 会话管理实例

1、获取Session(如果没有session，则会自动创建一个)

request.getSession();

2、获取session创建时间

Date createTime = new Date(session.getCreationTime());

3、获取最后访问时间

 Date lastAccessTime = new Date(session.getLastAccessedTime());

4、设置attribute（键值对形式）

 session.setAttribute(Key, value);

5、获取attribute

session.getAttribute(Key);

6、获取session id

session.getId();

7、日期格式

 SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

df.format(Date);

package com.masorl;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

@WebServlet("/SessionDemo")
public class SessionDemo extends HttpServlet{
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        如果没有Session，getSession会创建一个session对象
        HttpSession session = req.getSession(true);

//        获取session创建时间
        Date createTime = new Date(session.getCreationTime());
//        获取该网页的最后一次访问时间
        Date lastAccessTime = new Date(session.getLastAccessedTime());
//        设置日期输出的格式
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");


        int visitCount = 1;
        String visitCountKey = "visitCount";
        String userIDKey = "userID";
        String userID = "lee";

        if(session.isNew()){
            session.setAttribute(userIDKey, userID);
        }else{
            visitCount = (Integer)session.getAttribute(visitCountKey);
            visitCount = visitCount + 1;
            userID = (String)session.getAttribute(userIDKey);
        }
        session.setAttribute(visitCountKey,visitCount);

        System.out.println("访问时间:  " + df.format(createTime));
        System.out.println("最后访问时间:  " + df.format(lastAccessTime));
        System.out.println( "id:  " + session.getId());
        System.out.println("用户id:  " + userID);
        System.out.println("访问次数:  " + visitCount);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}