redis之hash类型设置过期时间

redis 127.0.0.1:6379> hset expire:me name tom
(integer) 0
redis 127.0.0.1:6379> hget expire:me name
"tom"

redis 127.0.0.1:6379> expire expire:me 20
(integer) 1
redis 127.0.0.1:6379> ttl expire:me
(integer) 8

...
...
...

redis 127.0.0.1:6379> ttl expire:me
(integer) -1
redis 127.0.0.1:6379> hget expire:me name
(nil)