《Redis应用实例》Java实现（29）：优先队列

优先队列也是一种非常常见的数据结构，跟队列类似，只是队列中元素有优先级，根据优先级来进行排序。
redis中可以使用zset来实现优先队列。
 

package com.foxbill.redisinaction;import redis.clients.jedis.Jedis;
import java.util.List;/*** 优先队列*/
public class Chapter29 {static private String KEY_QUEUE = "Chapter29:queue";static public void start(Jedis jedis) {cleanData(jedis);for (int i = 0; i < 10; i++) {add(jedis,"item:"+String.valueOf(i),i);}String item = pop_max(jedis);System.out.printf("poped max item:%s\n", item);item = pop_min(jedis);System.out.printf("poped min item:%s\n", item);}//清除数据private static void cleanData(Jedis jedis) {jedis.del(KEY_QUEUE);}//添加指定优先级的元素到优先队列private static void add(Jedis jedis,String item,double priority) {jedis.zadd(KEY_QUEUE,priority, item);}//弹出优先级最小的元素private static String pop_min(Jedis jedis) {List<String> zrange = jedis.zrange(KEY_QUEUE, 0, 0);String item = zrange.get(0);jedis.zrem(KEY_QUEUE, item);return item;}//弹出优先级最大的元素private static String pop_max(Jedis jedis) {List<String> zrange = jedis.zrange(KEY_QUEUE, -1, -1);String item = zrange.get(0);jedis.zrem(KEY_QUEUE, item);return item;}}