1. 设置值 hset key field value
2. 获取值 hget key field
3. 删除field hdel key field [field ...]
4. 计算field个数 hlen key
5. 批量设置或获取
hmset key field value [field value ...]
hmget key field [field ...]
6. 判断field是否存在 hexists key field
7. 获取所有field hkeys key
8. 获取所有value hvals key
9. 获取所有field-value hgetall key
10. 计算value的字符串长度 hstrlen key field