Session_快速入门_hehe.employment.over.16.5

16.11 会话技术_Session_快速入门

• Session：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 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)
• 示例：

package com.xww.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("name","xww");
    }

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

package com.xww.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 name = session.getAttribute("name");
        System.out.println(name);//xww
    }

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

16.12 会话技术_Session_原理分析

• Session的实现是依赖于Cookie的。
• 图示：