Redis之hash类型

redis的hash类型，就像Java中的Map<String, Map<Object,Object>>

1. 设置一个字段/获取一个字段

设置一个字段：HSET key field value
获取一个字段：HGET key field

127.0.0.1:6379> hset user id 1
(integer) 1
127.0.0.1:6379> hget user id
"1"

2. 获取所有字段值

HGETALL key

127.0.0.1:6379> hgetall user
1) "id"
2) "1"

3. 判断字段是否存在

HEXISTS key field
存在返回1，不存在返回0.

127.0.0.1:6379> hexists user id
(integer) 1
127.0.0.1:6379> hexists user name
(integer) 0
127.0.0.1:6379> hgetall user
1) "id"
2) "1"

4. 设置多个字段/获取多个字段

设置多个字段：HMSET key field value [field value …]
获取多个字段：HMGET key field [field …]

127.0.0.1:6379> hgetall user
1) "id"
2) "1"
127.0.0.1:6379> hmset user name zhangsan address xian score 99
OK
127.0.0.1:6379> hmget user id name
1) "1"
2) "zhangsan"
127.0.0.1:6379> hmget user id name address score
1) "1"
2) "zhangsan"
3) "xian"
4) "99"
127.0.0.1:6379> hgetall user
1) "id"
2) "1"
3) "name"
4) "zhangsan"
5) "address"
6) "xian"
7) "score"
8) "99"

5. 只获取字段名/字段值

获取字段名：HKEYS key
获取字段值：HVALS key

127.0.0.1:6379> hgetall user
1) "id"
2) "1"
3) "name"
4) "zhangsan"
5) "address"
6) "xian"
7) "score"
8) "99"
127.0.0.1:6379> hkeys user
1) "id"
2) "name"
3) "address"
4) "score"
127.0.0.1:6379> hvals user
1) "1"
2) "zhangsan"
3) "xian"
4) "99"
127.0.0.1:6379> hvals person
(empty list or set)
127.0.0.1:6379> hkeys person
(empty list or set)

6. 获取某个key内全部数量

HLEN key

127.0.0.1:6379> hgetall user
1) "id"
2) "1"
3) "name"
4) "zhangsan"
5) "address"
6) "xian"
7) "score"
8) "99"
127.0.0.1:6379> hlen user
(integer) 4

7. 增加数字

HINCRBY key field increment

127.0.0.1:6379> hget user id
"1"
127.0.0.1:6379> hincrby user id 5
(integer) 6
127.0.0.1:6379> hget user id
"6"

8. 删除key内字段

HDEL key field

127.0.0.1:6379> hgetall user
1) "id"
2) "6"
3) "name"
4) "zhangsan"
5) "address"
6) "xian"
7) "score"
8) "99"
127.0.0.1:6379> hkeys user
1) "id"
2) "name"
3) "address"
4) "score"
127.0.0.1:6379> hdel user address
(integer) 1
127.0.0.1:6379> hgetall user
1) "id"
2) "6"
3) "name"
4) "zhangsan"
5) "score"
6) "99"
127.0.0.1:6379> hkeys user
1) "id"
2) "name"
3) "score"

9. 字段不存在时赋值

HSETNX key field value

127.0.0.1:6379> hkeys user
1) "id"
2) "name"
3) "score"
127.0.0.1:6379> hsetnx user address xian
(integer) 1
127.0.0.1:6379> hkeys user
1) "id"
2) "name"
3) "score"
4) "address"
127.0.0.1:6379> hvals user
1) "6"
2) "zhangsan"
3) "99"
4) "xian"
127.0.0.1:6379> hgetall user
1) "id"
2) "6"
3) "name"
4) "zhangsan"
5) "score"
6) "99"
7) "address"
8) "xian"
127.0.0.1:6379> hsetnx user score 98
(integer) 0
127.0.0.1:6379> hgetall user
1) "id"
2) "6"
3) "name"
4) "zhangsan"
5) "score"
6) "99"
7) "address"
8) "xian"

10. 应用场景

• 购物车

用户id为100的用户购物车，买了商品item1 1件, 商品item2 1件，然后增加商品item2 到4件，查看用户总共买了多少商品，每个商品分别是多少。

127.0.0.1:6379> hset shopcar:uid100 item1 1
(integer) 1
127.0.0.1:6379> hset shopcar:uid100 item2 1
(integer) 1
127.0.0.1:6379> hincrby shopcar:uid100 item2 3
(integer) 4
127.0.0.1:6379> hlen shopcar:uid100
(integer) 2
127.0.0.1:6379> hgetall shopcar:uid100
1) "item1"
2) "1"
3) "item2"
4) "4"