hgetall(hash get all) 获取一个key的所有字段和数据

127.0.0.1:6379> keys *
1) "user:1"
127.0.0.1:6379> exists user:1
(integer) 1
127.0.0.1:6379> hkeys user:1
1) "name"
2) "age"
127.0.0.1:6379> hgetall user:1
1) "name"
2) "youyi"
3) "age"
4) "20"