会话技术-Session-快速入门、原理分析

会话技术-Session-快速入门

　　1. 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

　　2. 快速入门：

　　　　1. 获取HttpSession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)

package com.example.day_16_cookidsession.session;

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;

@WebServlet("/sessionDemo1")
public class SessionDemo1 extends HttpServlet {
    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");
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }
}

package com.example.day_16_cookidsession.session;

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;

@WebServlet("/sessionDemo2")
public class SessionDemo2 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //使用session获取数据

        //1.获取session
        HttpSession session = request.getSession();
        //2.获取数据
        Object msg = session.getAttribute("msg");
        System.out.println(msg);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }
}