code: public long length() {
  		try {
  			if (isCluster(groupName)) {
  				return getBinaryJedisClusterCommands(groupName).hlen(keyBytes);
  			} else {
  				return getBinaryJedisCommands(groupName).hlen(keyBytes);
  			}
  		} finally {
  			getJedisProvider(groupName).release();
  		}
  	}
docs: 返回长度
  
  @return