单点登陆Redis存储session（重点）

1、cookie里面存放的jsessionid就是session里面存的session.getId();session里面存放的是用户登陆信息，也就是我们常说的token值

第一次登陆到tomcat1获得jsessionid和第二次到tomcat2获得jessionid肯定是不一样的

解决方案：

     将第一次登陆的sessionid（也就是token）以loginToken为健存储到redis里面去，后面登陆去redis里面去读取loginToken，

     将cookie里面获得token值以loginToken为键，token值为value存在cookie里面

     直接从cookie里面读取loginToken的值，然后在redis里面去获取用户信息

2、启动项目tomcat的设置

第一步：书写CookieUtil类，如下：

package com.mmall.util;

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@Slf4j
public class CookieUtil {
    private final static String COOKIE_DOMAIN="mmall.com";
    private final static String COOKIE_NAME="mall_login_token";//自己定义一个名字作为健
    //读取cookie
    public static String readLoginToken(HttpServletRequest request){
        Cookie[] cks=request.getCookies();
        if(cks!=null){
            for(Cookie ck:cks){
                log.info("cookieName:{},cookieValue:{}",ck.getName(),ck.getValue());
                //这方法如果ck.getName()是空的话，这方法不会报空指针异常
                if(StringUtils.equals(ck.getName(),COOKIE_NAME)){
                    log.info("return cookieName:{},cookieValue:{}",ck.getName(),ck.getValue());
                    return ck.getValue();
                }
            }
        }
            return null;
    }
    //写入cookie，将cookie里面获得token值以loginToken为键，token值为value存在cookie里面
    public static void writeLoginToken(HttpServletResponse response,String token){
        Cookie ck =new Cookie(COOKIE_NAME,token);
        ck.setDomain(COOKIE_DOMAIN);
        ck.setPath("/");//代表设置在根目录
        ck.setHttpOnly(true);//无法通过脚本获取cookie信息
        //如果maxAge不设置，cookie就不会写入硬盘，而写入内存，只在当前页面有效
        ck.setMaxAge(60*60*24*365);//-1代表永久，单位是秒
        log.info("write cookieName:{},cookieValue:{}",ck.getName(),ck.getValue());
        response.addCookie(ck);
    }
   //注销登陆，将这个cookie删除
    public static void delLoginToken(HttpServletRequest request,HttpServletResponse response){
        Cookie[] cks=request.getCookies();
        if(cks!=null){
            for(Cookie ck:cks){
                if(StringUtils.equals(ck.getName(),COOKIE_NAME)){
                    ck.setDomain(COOKIE_DOMAIN);
                    ck.setPath("/");
                    ck.setMaxAge(0);//0代表删除此cookie
                    log.info("del cookieName:{},cookieValue:{}",ck.getName(),ck.getValue());
                    response.addCookie(ck);//返回有效期为0的cookie，浏览器将删除此cookie
                    return;
                }
            }
        }
    }
}

第二步：书写controller类

用户登陆

    /**
     * 用户登录
     * @param username
     * @param password
     * @param session
     * @return
     */
    @RequestMapping(value = "login.do",method = RequestMethod.POST)
    @ResponseBody
    public ServerResponse<User> login(String username, String password, HttpSession session, HttpServletResponse httpServletResponse, HttpServletRequest httpServletRequest){
        ServerResponse<User> response = iUserService.login(username,password);
        if(response.isSuccess()){
            //session.setAttribute(Const.CURRENT_USER,response.getData());
            //将cookie写入到response里面去
            CookieUtil.writeLoginToken(httpServletResponse,session.getId());
            RedisPoolUtil.setEx(session.getId(), JsonUtil.obj2String(response.getData()),Const.RedisCacheExtime);
        }
        return response;
    }

获取用户信息

    //tomcat搭建集群后，获取用户信息从redis里面去拿
    @RequestMapping(value = "get_user_info.do",method = RequestMethod.POST)
    @ResponseBody
    public ServerResponse<User> getUserInfo(HttpSession session,HttpServletRequest httpServletRequest){
        //User user = (User) session.getAttribute(Const.CURRENT_USER);
        //直接从cookie里面读取loginToken的值，然后在redis里面去获取用户信息
        String loginToken=CookieUtil.readLoginToken(httpServletRequest);
        if(StringUtils.isEmpty(loginToken)){
            return ServerResponse.createByErrorMessage("用户未登录,无法获取当前用户的信息");
        }
        //获取用户的信息
        String userJsonStr=RedisPoolUtil.get(loginToken);
        User user = JsonUtil.string2Obj(userJsonStr,User.class);
        if(user != null){
            return ServerResponse.createBySuccess(user);
        }
        return ServerResponse.createByErrorMessage("用户未登录,无法获取当前用户的信息");
    }

用户登出

  @RequestMapping(value = "logout.do",method = RequestMethod.POST)
    @ResponseBody
    public ServerResponse<String> logout(HttpSession session,HttpServletRequest httpServletRequest,HttpServletResponse httpServletResponse){
        String loginToken=CookieUtil.readLoginToken(httpServletRequest);
        //在cookie里面删除loginToken
        CookieUtil.delLoginToken(httpServletRequest,httpServletResponse);
        //在redis里面删除loginToken
        RedisPoolUtil.del(loginToken);
        //session.removeAttribute(Const.CURRENT_USER);
        return ServerResponse.createBySuccess();
    }