方便jedis cluster操作的工具类

由于redis的集群 redis cluster不支持keys这样的多key操作（具体原因由于sharding 后，不同的key属于不同的slot,难以支持原子操作）。所以如果一个对外需要对缓存做失效处理时比较棘手。所以本类提供工具方法再redis cluster查找按照hashTags处理的keys和一般的keys。基于jedis cluster实现。

有优化空间，现在懒得改了

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;

import org.apache.commons.collections4.CollectionUtils;

import com.google.common.collect.Lists;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisCluster;
import redis.clients.jedis.JedisPool;
import redis.clients.util.JedisClusterCRC16;

public interface RedisCacheSupporter {

	String SEPARATOR = RedisCacheBase.staticSeparator();

	String CONJUNCTION = RedisCacheBase.staticConjunction();

	String PLACEHOLDER = RedisCacheBase.staticPlaceHolder();

	String LEFT_TAG_STR = RedisCacheBase.staticLeftTagStr();

	String RIGHT_TAG_STR = RedisCacheBase.staticRightTagStr();

	static String hashTagsPrefix(String cacheKeyPrefix) {
		
		return LEFT_TAG_STR + cacheKeyPrefix + RIGHT_TAG_STR;
	}
	
	static TreeSet<String> keys(JedisCluster jedisClusterClient, String cachePrefix) {

		Map<String, JedisPool> clusterNodes = jedisClusterClient.getClusterNodes();
		TreeSet<String> keys = new TreeSet<>();
		String strPattern = cachePrefix + "*";
		for (String k : clusterNodes.keySet()) {

			JedisPool jp = clusterNodes.get(k);
			try (Jedis jedis = jp.getResource();) {

				if (jedis.info("replication").contains("role:slave"))
					continue;
				
				Set<String> keysInNode = jedis.keys(strPattern);
				keys.addAll(keysInNode);
			}
		}
		return keys;
	}
	
	static boolean delByKey(JedisCluster jedisClusterClient, String cacheKey) {
		
		return jedisClusterClient.del(cacheKey) > 0;
	}
	
	/**
	 * 缓存前缀通过hash tags {@link #hashTagsPrefix(String)}处理过的key首选使用本方法
	 * <br/>
	 * <br/>
	 * hash tags在redis集群reSharding时，不能保证都在同一slot下，所以为代码健壮性考虑可首先调用本方法再捕获异常中调用{@link #delLoopNodesByPrefix(JedisCluster, String)}方法处理
	 * @param jedisClusterClient
	 * @param cachePrefix
	 */
	static void delAllByPrefix(JedisCluster jedisClusterClient, String cachePrefix) {
		
		Set<String> keys = keys(jedisClusterClient, cachePrefix);
		if (CollectionUtils.isEmpty(keys)) {
			
			return;
		}
		
		jedisClusterClient.del(keys.toArray(new String[keys.size()]));
	}
	
	static void delLoopNodesByPrefix(JedisCluster jedisClusterClient, String cachePrefix) {

		String keysPattern = cachePrefix + "*";
		Map<String, JedisPool> clusterNodes = jedisClusterClient.getClusterNodes();
		for (String k : clusterNodes.keySet()) {

			JedisPool jedisPool = clusterNodes.get(k);
			try (Jedis jedis = jedisPool.getResource()) {

				if (jedis.info("replication").contains("role:slave"))
					continue;// 从节点不处理

				Set<String> keys = jedis.keys(keysPattern);
				if (keys.size() <= 0)
					continue;

				Map<Integer, List<String>> map = new HashMap<>();
				for (String key : keys) {

					// cluster模式执行多key操作的时候，这些key必须在同一个slot上
					// 不然会报:redis.clients.jedis.exceptions.JedisClusterException:
					// No way to dispatch this command to Redis Cluster because keys have different slots.
					int slot = JedisClusterCRC16.getSlot(key);
					// 按slot将key分组，相同slot的key一起提交
					if (map.containsKey(slot)) {
						map.get(slot).add(key);
					} else {
						map.put(slot, Lists.newArrayList(key));
					}
				}

				for (Integer slotKey : map.keySet()) {
					jedis.del(map.get(slotKey).toArray(new String[map.get(slotKey).size()]));
				}
			}
		}
	}
	
}