hdel(hash del) 移除单个或多个字段

127.0.0.1:6379> keys *
1) "user:1"
127.0.0.1:6379> hgetall user:1
1) "name"
2) "adc"
3) "age"
4) "17"
127.0.0.1:6379> hdel user:1 name age
(integer) 2
127.0.0.1:6379> keys *
(empty list or set)