Redis適用於高並發的遞增、遞減功能

遞增指令：incr（默認從0開始）

遞減指令：decr（默認從0開始，遞減會出現負數，這點跟memcache不一樣,mc到0）

如下：

附上shardedJedisPool和JedisCluster的兩種實現方式：

shardedJedisPool：

@Override
    public Long decr(String key) {
        ShardedJedis jedis = null;
        Long result = 0l;
        try {
            jedis =  shardedJedisPool.getResource();
            result = jedis.decr(key);
        } catch (Exception e) {
            log.error("redis decr error and key = " + key, e);
        }
        return result;
    }

    @Override
    public Long incr(String key) {
        ShardedJedis jedis = null;
        Long result = 0l;
        try {
            jedis =  shardedJedisPool.getResource();
            result = jedis.incr(key);
        } catch (Exception e) {
            log.error("redis incr error and key = " + key, e);
        }
        return result;
    }

JedisCluster：

@Override
    public Long decr(String key) {
        Long result = 0l;
        try {
            result = jedisCluster.decr(key);
        } catch (Exception e) {
            log.error("jedisCluster decr error and key = " + key, e);
        }
        return result;
    }

    @Override
    public Long incr(String key) {
        Long result = 0l;
        try {
            result = jedisCluster.incr(key);
        } catch (Exception e) {
            log.error("jedisCluster incr error and key = " + key, e);
        }
        return result;
    }

適用場景：

　　高並發生成訂單號，秒殺類的業務邏輯等。。