redis优先级队列探究

 

redis优先级队列

参考下面的连接 由于zadd可以设置score, 越大表示排序越靠前，如果相同按照默认的排序来排列，因此可以通过设置score来设置队列的优先级顺序。

//==========================start=================================

package com.test;

import org.junit.Test;
import redis.clients.jedis.Jedis;

import java.util.Iterator;
import java.util.Set;

/**
* User: weichun.zhan
* Date: 12-7-30
* Time: 下午12:17
*/
public class TestRedisQueue {

    @Test
    public void testQeuePriority1(){
        JedisManager manager = JedisManager.getInstance();
        Jedis jedis = manager.getResource();
        //方式一：把队列值放入队列头
        long r = jedis.lpush("derekzhan","1");
        System.out.println(" result1:" + r);
        jedis.lpush("derekzhan","2");
        jedis.lpush("derekzhan","3");

        long r4 = jedis.rpush("derekzhan", "4");
        System.out.println(" result2:" + r4);
        long l = jedis.lpush("derekzhan","5");
        System.out.println(" result3:" + l);

        String value = null;
        while( null != (value = jedis.rpop("derekzhan"))){
            System.out.println(value);
        }
        manager.returnResource(jedis);
    }
    @Test
    public void testQeuePriority2(){
        JedisManager manager = JedisManager.getInstance();
        Jedis jedis = manager.getResource();
        long start = System.currentTimeMillis();
        //方式二：移动队列中指定的值到对列头
        System.out.println("--------------------------");

        for(int i = 0 ;i < 10000;i++){
            jedis.lpush("derekzhan", "" + i);
        }

        String val = null;
        String find = "3000";
        while(true)
        {
            val =  jedis.rpoplpush("derekzhan", "derekzhan");
            //System.out.println("val = " + val);
            if(find.equals(val)){
                val =  jedis.lpop("derekzhan");
                jedis.rpush("derekzhan",val);
                break;
            }
        }



        String value = null;
        while( null != (value = jedis.rpop("derekzhan"))){
            //System.out.println(value);
        }
        System.out.println("took time:" + (System.currentTimeMillis() - start));
        manager.returnResource(jedis);
    }
    @Test
    public void testQeuePriority3(){
        JedisManager manager = JedisManager.getInstance();
        Jedis jedis = manager.getResource();
        long start = System.currentTimeMillis();
        //方式二：移动队列中指定的值到对列头
        for(int i = 0 ;i < 10000;i++){
            jedis.lpush("derekzhan", "" + i);
        }

        String val = null;
        int i = 0;
        String find = "3000";
        while(true)
        {
            val =  jedis.lindex("derekzhan", i);
            //System.out.println("val = " + val);
            i++;
            if(find.equals(val)){
                jedis.lrem("derekzhan",0,find);
                jedis.rpush("derekzhan",val);
                break;
            }
        }



        String value = null;
        while( null != (value = jedis.rpop("derekzhan"))){
            //System.out.println(value);
        }
        System.out.println("took time:" + (System.currentTimeMillis() - start));
        manager.returnResource(jedis);
    }

    /**
     * redis优先级队列
     */
    @Test
    public void TestQueuePriority(){
        JedisManager manager = JedisManager.getInstance();
        Jedis jedis = manager.getResource();
        long start = System.currentTimeMillis();
        //重新调整队列的score值让此值处于队列的头  此种方式比上面的2种方式都要好，效率最高，
        //但可能要维护多个score值，还有个问题是如果score一样，则按照默认的倒叙排列,值越大在队列头
        String _name = "derekzhan";
        jedis.zadd(_name,1,"2");
        jedis.zadd(_name,1,"4");
        jedis.zadd(_name,1,"3");
        jedis.zadd(_name,3,"40");
        jedis.zadd(_name,3,"10");

        for(int i = 0 ;i < 5000;i++){
            jedis.zadd(_name,1,""+i);
        }
        for(int i = 5000 ;i < 10000;i++){
            jedis.zadd(_name,2,""+i);
        }

        String find = "3000";
        jedis.zadd(_name,3,find);



        //System.out.println(jedis.zrevrange(_name,0,-1));

        while (true){
            boolean hasValue = false;
            Set val = jedis.zrevrange(_name,0,0);//从队列中获取一个数据.
            for (Iterator iterator = val.iterator(); iterator.hasNext();) {
                Object next =  iterator.next();
                System.out.println(next);

                //proccess operation........
                jedis.zrem(_name,next.toString());
                if(!next.equals(find)){
                    hasValue = true;
                }else {
                    hasValue = false;
                    System.out.println(next);
                }
            }
            if(!hasValue){
                break;
            }
        }
        System.out.println("took time:" + (System.currentTimeMillis() - start));
        manager.returnResource(jedis);
    }
}

//==========================end=================================

来源：http://www.cnblogs.com/liuhao/archive/2012/06/26/2563702.html