递增指令：incr（默认从0开始）

递减指令：decr（默认从0开始，递减会出现负数，这点跟memcache不一样,mc到0）

如下：

附上shardedJedisPool和JedisCluster的两种实现方式：

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;    }

适用场景：

　　高并发生成订单号，秒杀类的业务逻辑等。。