使用redis管理用户登录会话的方法

import java.util.ArrayList;import java.util.Set;import redis.clients.jedis.Jedis;public class Login { public String checkToken(Jedis conn,String token){  return conn.hget("login:", token); } public void updateToken(Jedis conn,String token,String user,String item){  long time=System.currentTimeMillis()/1000;  conn.hset("login:", token, user);//维持令牌与用户之间的映射  conn.zadd("recent:", time, token);//保存令牌最后一次出现的时间  if(item!=null){   conn.zadd("viewd:"+token, time, item);//根据这个令牌来设置该用户在这个时间戳访问的商品名字   conn.zremrangeByRank("viewd:"+token, 0, -26);//移除就的用户记录，只保留用户浏览过的25个商品。   conn.zincrby("viewd:", -1, item);  } } public class CleanSessionsThread extends Thread{  private Jedis conn;  private int limit;  private boolean quit;  public CleanSessionsThread(int limit) {   // TODO Auto-generated constructor stub   this.conn=new Jedis("localhost");   conn.select(15);   this.limit=limit;  }  public void quit(){   quit=true;  }  @Override  public void run() {   // TODO Auto-generated method stub   while(!quit){    long size=conn.zcard("recent:");//依据登录时间确定在线人数    if(size<=limit){     try {      Thread.sleep(1000);     } catch (InterruptedException e) {      // TODO Auto-generated catch block      e.printStackTrace();     }    }else{     long endIndex=Math.min(size-limit,100);     Set<String> tokensSet=conn.zrange("recent:", 0, endIndex-1);     String[] tokens=tokensSet.toArray(new String[tokensSet.size()]);     ArrayList<String> sessionKeys=new ArrayList<>();     for(String token:tokens){      sessionKeys.add("viewd:"+token);     }     conn.del(sessionKeys.toArray(new String[sessionKeys.size()]));     conn.hdel("login:", tokens);     conn.zrem("recent:", tokens);    }   }  } }}