会话技术-Cookie-快速入门、原理分析

会话技术-Cookie-快速入门

　　1. 概念：客户端会话技术，将数据保存到客户端

　　2. 快速入门：
　　　　使用步骤：
　　　　　　1. 创建Cookie对象，绑定数据
　　　　　　　　new Cookie(String name, String value)
　　　　　　2. 发送Cookie对象
　　　　　　　　response.addCookie(Cookie cookie)
　　　　　　3. 获取Cookie，拿到数据
　　　　　　　　Cookie[] request.getCookies()

package com.example.day_16_cookidsession.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("/cookieDemo1")
public class CookieDemo1 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.创建Cookie对象
        Cookie c = new Cookie("msg","hello");
        //2.发送Cookie
        response.addCookie(c);
    }

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

package com.example.day_16_cookidsession.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("/cookieDemo2")
public class CookieDemo2 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
       //3. 获取Cookie
        Cookie[] cs = request.getCookies();
        //获取数据，遍历Cookies
        if(cs != null){
            for (Cookie c : cs) {
                String name = c.getName();
                String value = c.getValue();
                System.out.println(name+":"+value);
            }
        }
    }

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