redis 笔记

1. string

1.1 string常用命令

set,get

127.0.0.1:6379> set user:key userValue
OK
127.0.0.1:6379> get user:key
"userValue"

mset,mget

假如我要存储多个key value，如用户信息 {“name”:“zhangsan”,“age”:“12”,“password”:“123456”}

用set,get的话，需要1.取出json 2.解析json 3.修改json 4.转成json 5.进行存储

用mget 和mset 就特别方便

127.0.0.1:6379> mset user:zhangsan:name zhangsan user:zhangsan:age 12 user:zhangsan:password 123456
OK
# 取出所有字段
127.0.0.1:6379> mget user:zhangsan:name user:zhangsan:age  user:zhangsan:password
1) "zhangsan"
2) "12"
3) "123456"
# 修改其中一个字段
127.0.0.1:6379> mset user:zhangsan:age 15
OK
127.0.0.1:6379> mget user:zhangsan:name user:zhangsan:age  user:zhangsan:password
1) "zhangsan"
2) "15"
3) "123456"

setnx 当有当前key时，不做任何操作，当没有时，做插入操作

127.0.0.1:6379> setnx nxtest nxvalue
(integer) 1
127.0.0.1:6379> get nxtest
"nxvalue"
127.0.0.1:6379> setnx nxtest nxvalue123
(integer) 0
127.0.0.1:6379> get nxtest
"nxvalue"

incr 计数器

127.0.0.1:6379> incr article:readcount:1001
(integer) 1
127.0.0.1:6379> incr article:readcount:1001
(integer) 2
127.0.0.1:6379> incr article:readcount:1001
(integer) 3
127.0.0.1:6379> incr article:readcount:1001
(integer) 4
127.0.0.1:6379> get article:readcount:1001
"4"

1.2 string 的应用场景

springsession

分表里面的维护全局序列号

每次取出1000个id

127.0.0.1:6379> incrby sequence:tablename 1000
(integer) 1000
127.0.0.1:6379>  incrby sequence:tablename 100
(integer) 1100
127.0.0.1:6379>  incrby sequence:tablename 1000
(integer) 2100

将1000个数据存到本地缓存

比如：取出的数据是2100，则可以使用的id范围是 1100 ~ 2100
用完了再次获取

2. hash

2.1 hash 常用命令

结构为，key-map

hset 设置map 属性 hset key field value

127.0.0.1:6379> hset hash:user:zhangsan name zhangsan
(integer) 1
127.0.0.1:6379> hset hash:user:zhangsan age 12
(integer) 1

hget 取出value的值 hget key fied

127.0.0.1:6379> hget hash:user:zhangsan name
"zhangsan"

hsetnx 存储一个不存在的map hsetnx key field value

127.0.0.1:6379> hsetnx hsetnx:user:zhangsan name zhangsan
(integer) 1
127.0.0.1:6379> hget hsetnx:user:zhangsan name
"zhangsan"
127.0.0.1:6379> hsetnx hsetnx:user:zhangsan name zhangsan123
(integer) 0
127.0.0.1:6379> hget hsetnx:user:zhangsan name
"zhangsan"

hmset 多个键值对一块存储 hmset key field1 value1 field2 value2

127.0.0.1:6379> hmset hmset:user name zhangsan age 14 password 123456
OK
127.0.0.1:6379> hget hmset:user name
"zhangsan"
127.0.0.1:6379>

hmget 多个键值对一块取 hmget key field1 field2 field3

127.0.0.1:6379> hmget hmset:user name age password
1) "zhangsan"
2) "14"
3) "123456"

hdel 删除hash表中 field的值 hdel key field [field …]

127.0.0.1:6379> hdel  hmset:user name password
(integer) 2
127.0.0.1:6379> hmget hmset:user name age password
1) (nil)
2) "14"
3) (nil)
127.0.0.1:6379>

hlen 返回hash表中field的数量 hlen key

127.0.0.1:6379> hlen  hmset:user
(integer) 1

hgetall 返回所有hash表中所有的键值 hgetall key

127.0.0.1:6379> hmset hmset:user name zhangsan age 14 password 123456
OK
127.0.0.1:6379> hgetall hmset:user
1) "age"
2) "14"
3) "name"
4) "zhangsan"
5) "password"
6) "123456"

hincrby 为hash表中field中的值加上增量 increment hincrby key field

127.0.0.1:6379> hincrby hmset:user increment 10
(integer) 10
127.0.0.1:6379>  hget hmset:user increment
"10"

2.2 hash应用场景

购物车的实现
1. 以用户id为key,商品id为field ,商品数量为value
2. 添加购物车添加商品id为1001 到zhangsan的购物车，添加数量为1
```
127.0.0.1:6379> hset car:zhangsan 1001 1
(integer) 1
127.0.0.1:6379> hget car:zhangsan 1001
"1"
```
3. 增加数量将zhangsan的购物车中的商品id为1001的增加一个
```
127.0.0.1:6379> hincrby car:zhangsan 1001 1
(integer) 2
```
4. 购物车中的商品总数获取zhangsan购物车中的商品的总数
```
# 之前增加了 1001和1002 两个商品
127.0.0.1:6379> hlen car:zhangsan
(integer) 2
```
1. 删除商品移除 zhangsan购物初中id为1001的商品
```
127.0.0.1:6379> hdel car:zhangsan 1001
(integer) 1
```
2. 获取所有商品列表获取zhangsan购物车的所有列表
```
127.0.0.1:6379> hgetall car:zhangsan
1) "1002"
2) "1"
```

3. list

3.1 list 常用命令

lpush 将一个或多个插入到列表的左侧 lpush key value [value …]
```
127.0.0.1:6379> lpush lpush:info zhangsan lisi wangwu
(integer) 3
```
rpush 将一个或多个插入到列表的右侧 rpush key value [value …]
```
127.0.0.1:6379> rpush lpush:info aa bb cc
(integer) 6
```
lpop 移除最左头元素,并返回移除的元素 lpop key
```
127.0.0.1:6379> lpop lpush:info
"wangwu"
```
rpop 移除最右侧头元素,并返回移除的元素 rpop key
```
127.0.0.1:6379> rpop lpush:info
"cc"
```

lreange 返回区间范围的列表 lrange key start end

# 目前里面的元素从左至右依次是 lisi,zhangsan,aa,bb
127.0.0.1:6379> lrange lpush:info 2 3
1) "aa"
2) "bb"
127.0.0.1:6379>  lrange lpush:info 1 3
1) "zhangsan"
2) "aa"
3) "bb"
127.0.0.1:6379> lrange lpush:info 0 3
1) "lisi"
2) "zhangsan"
3) "aa"
4) "bb"

blpop 从key列表中弹出左侧第一个元素，若列表中没有该元素，阻塞等到timeout秒，如果timeout=0,则一直阻塞 blpop key [key…] timeout

# 一直阻塞
127.0.0.1:6379>  blpop blpush:info 0
    
# 向blpush:info添加 zhangsan
127.0.0.1:6379> lpush blpush:info zhangsan
(integer) 1
    
# 弹出第一个元素
127.0.0.1:6379>  blpop blpush:info 0    
1) "blpush:info"
2) "zhangsan"
(34.55s)

brpop 从key列表中弹出右侧第一个元素，若列表中没有该元素，阻塞等到timeout秒，如果timeout=0,则一直阻塞 brpop key [key…] timeout

# 一直阻塞
127.0.0.1:6379>  brpop brpush:info 0
    
# brpush:info添加 zhangsan
127.0.0.1:6379> lpush brpush:info aa
(integer) 1
    
# 弹出第一个元素
127.0.0.1:6379>  brpop brpush:info 0    
1) "brpush:info"
2) "aa"
(12.55s)

3.2 list 应用场景

stack 栈

Stack = lpush + lpop 先进后出
queue队列

Queue = lpush + rpop 先进先出
blocking mq 阻塞队列

Blocking MQ = lpush + brpop

4. set

4.1set 常用命令

sadd 往集合key中存入元素，若元素存在则忽略，不存在的新增

sadd key member [member…]

127.0.0.1:6379> sadd set:info zhangsan lisi wangwu
(integer) 3
# 此处因为zhangsan已经存在，则忽略
127.0.0.1:6379> sadd set:info zhangsan aa
(integer) 1

srem 从集合key中删除元素

srem key member [members]
```
127.0.0.1:6379> srem set:info aa
(integer) 1
```

smembers 获取key中所有元素

smembers key

127.0.0.1:6379> smembers set:info
1) "zhangsan"
2) "wangwu"
3) "lisi"

scard 获取元素的个数

scard key

127.0.0.1:6379> scard set:info
(integer) 3

sismember 判断元素是否在集合中

sismember key member

127.0.0.1:6379> sismember set:info zhangsan
(integer) 1

srandmember 从集合key中随机选出count个元素，元素不从key中删除

srandmember key count

127.0.0.1:6379> srandmember set:info 2
1) "lisi"
2) "wangwu"
127.0.0.1:6379> srandmember set:info 2
1) "lisi"
2) "wangwu"
127.0.0.1:6379> srandmember set:info 2
1) "zhangsan"
2) "lisi"

spop 从集合key中随机选出count个元素，元素从key中删除

spop key count

127.0.0.1:6379> smembers set:info
1) "zhangsan"
2) "wangwu"
3) "lisi"
127.0.0.1:6379> spop set:info 1
1) "zhangsan"
127.0.0.1:6379> smembers set:info
1) "wangwu"
2) "lisi"
127.0.0.1:6379>

sinter 交集运算

sinter key [key…]

127.0.0.1:6379> sadd set:01 aa bb cc
(integer) 3
127.0.0.1:6379> sadd set:02 bb cc dd
(integer) 3
127.0.0.1:6379> sinter set:01 set:02
1) "cc"
2) "bb"
127.0.0.1:6379>

sinterstore 将交集运算存入新的集合中

sinterstote newKey key [key…]

127.0.0.1:6379> sinterstore set:03 set:01 set:02
(integer) 2
127.0.0.1:6379> smembers set:03
1) "bb"
2) "cc"

sunion 并集运算

sunion key [keys]

127.0.0.1:6379> sunion set:01 set:02
1) "dd"
2) "cc"
3) "bb"
4) "aa"

sunionstore 将并集运算存入新的集合中

sunionstore newkey key [key…]

127.0.0.1:6379> sunionstore set:04 set:01 set:02
(integer) 4
127.0.0.1:6379> smembers set:04
1) "dd"
2) "cc"
3) "bb"
4) "aa"

sdiff 差集运算

sdiff key [key…]

127.0.0.1:6379> sdiff set:01 set:02
1) "aa"

sdiffstore 将差集运算存入新的集合中

sdiffstore newkey key [key…]

127.0.0.1:6379> sdiffstore set:05 set:01 set:02
(integer) 1
127.0.0.1:6379> smembers set:05
1) "aa"
127.0.0.1:6379>

4.2 set应用场景

抽奖小程序
1. 点击参与抽奖
  
  sadd key userId
2. 查看参与抽奖所有用户
  
  smembers key
3. 抽取count名中中奖者
  
  srandmember key count / spop key count
微信，微博点赞收藏标签
1. 点赞
  
  sadd like:{消息id} userID
2. 取消点赞
  
  srem like:{消息id} userID
3. 检查用户是否点过赞
  
  sismember like:{消息id} userID
4. 获取点赞的用户列表
  
  smembers like:{消息id}
5. 获取顶赞用户数
  
  scard like:{消息id}

5. zset

5.1 zset 常用命令

zadd 往有序集合中加入带分值元素

zadd key score member [score member …]

127.0.0.1:6379> zadd zset:info 1 zhangsan 2 lisi 3 wangwu
(integer) 3

zrem 删除元素

zrem key member [member…]

127.0.0.1:6379> zrem zset:info zhangsan
(integer) 1
127.0.0.1:6379> zrange zset:info 0 10
1) "lisi"
2) "wangwu"

zscore 返回member的分值

zscore key member

127.0.0.1:6379>  zscore zset:info lisi
"2"

zincrby 为member增加分值

zincrby key increment menber

127.0.0.1:6379> zincrby zset:info 2 lisi
"4"
127.0.0.1:6379> zscore zset:info lisi
"4"

zcard 返回集合中元素的个数

zcard key

127.0.0.1:6379> zcard zset:info
(integer) 2

zrange 正序获取集合中从start 到stop 下表的元素

zrange key start stop

127.0.0.1:6379> zadd zset:01 1 aa 2 bb 3 cc 4 dd 5 ee 6 ff
(integer) 6
127.0.0.1:6379> zrange zset:01 2 3
1) "cc"
2) "dd"

zrevrange 倒序获取集合中从start 到stop 下表的元素

zrevrange key start stop
```
127.0.0.1:6379> zrevrange zset:01 2 3
1) "dd"
2) "cc"
```

zunionstore 并集计算，将计算的结果存入新的key

zunionstore newkey numkeys key [key…] numkeys:计算key的数量，本次为2

127.0.0.1:6379> zadd zset:01 1 aa 2 bb 3 cc 4 dd 5 ee 6 ff
(integer) 6
127.0.0.1:6379> zadd zset:02 4 dd 5 ee 6 ff 7 gg 8 hh
(integer) 5
127.0.0.1:6379> zunionstore zset:03 2 zset:01 zset:02
(integer) 8

zinterstore 交集计算将计算的结果存入新的key

zinterstore newkey numkeys key [key…] numkeys:计算key的数量，本次为2
```
127.0.0.1:6379> zinterstore zset:04 2 zset:01 zset:02
(integer) 3
```

5.2 zset 应用场景

热搜排行榜
1. 点击新闻
  
  zincrby hotNews:20201101 1 守护香港
2. 展示当日排行前十
  
  zrevrange hotNews:20201101 0 9 withscores
3. 七日搜索榜单计算
  
  zunionstore hotNews:20201101-20201107 7 hotNews:20201101 hotNews:20201102 …hotNews:20201107
4. 展示七日排行前十
  
  zrevrange hotNews:20201101-20201107 0 9 withscores

redis 数据类型常用命令和应用场景