会话技术_Cookie快速入门和会话技术Cookie原理分析

会话技术

会话：一次会话中包含多次请求和响应。
- 一次会话：浏览器第一次给服务器资源发送请求，会话建立，知道有一方断开为止
功能：在一次会话的范围内的多次请求间，共享数据
方式：
- 客户端会话技术：Cookie
- 服务端会话技术：Session

概念：客户端会话技术，将数据保存到客户端
快速入门：
- 使用步骤：
  - 创建Cookie对象，绑定数据
    - new Cookie(String name，String value)
  - 发送Cookie对象
    - response.addCookie(Cookie cookie)
  - 获取Cookie，拿到数据
    - Cookie[] request.getCookies()

package com.ailyt.cookie;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;

/**
 *
 * Cookie快速入门
 *
 */

@WebServlet(value = "/CookieStudy01")
public class CookieStudy01 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 {
        //1.创建cookie对象
        Cookie cookie = new Cookie("msg","hello");
        //2.发送cookie
        response.addCookie(cookie);


    }
}

package com.ailyt.cookie;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 *
 * Cookie快速入门
 *
 */

@WebServlet(value = "/CookieStudy02")
public class CookieStudy02 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 {

        //3.获取cookie拿到数据
        Cookie[] cs = request.getCookies();
        //获取数据遍历Cookies
        for (Cookie cookie1 : cs) {
            System.out.println(cookie1.getName() + "--->" + cookie1.getValue());
        }

    }
}