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);
    }
   }
  }
 }
}