一文了解：Redis基础类型
Redis特点
开源的，BSD许可高级的key-value存储系统
可以用来存储字符串，哈希结构，链表，集合
安装
windows：https://github.com/microsoftarchive/redis/releases
mac\linux：http://www.redis.cn/
Redis 数据类型
Redis支持五种数据类型：string（字符串），hash（哈希），list（列表），set（集合）及zset（有序集合）。
string（字符串）
字符串类型是Redis的最基本数据结构。
字符串类型的值实际可以为字符串，数字，二进制，但是值最大不能超过512M。
| key | value |
|---|---|
| hello | world |
| counter | 1 |
| bits | 10000100 |
| json | {"id":1,"name":"xiaocai","age":18} |
string命令
设置
set key value [EX seconds] [PX milliseconds] [NX|XX]
get key
> set name xiaocai
OK
> get name
"xiaocai"过期
setex key seconds value
> set name1 redis1 ex 10 #10秒后过期
OK
> get name1
(nil)
> setex name2 10 redis2 #10秒后过期
OK
> get name2
"redis2"
> get name2
(nil)
> set name3 redis3 px 10 #10豪秒后过期
OK
> get name3
(nil)不存在才能设置成功或者必须存在才能设置成功
> set hello world nx #不存在才能设置成功
OK
> set hello w nx #存在就设置失败
(nil)
> get hello
"world"
>set hello w xx #存在才能设置成功
OK
> set world hello xx #不存在就设置失败
(nil)
> get hello
"w"
> get world
(nil)批量设置
mset key value [key value ...]
mget key [key ...]
> mset name1 redis1 name2 redis2
OK
> mget name1 name2
1) "redis1"
2) "redis2"
> mget name1 name2 name3
1) "redis1"
2) "redis2"
3) (nil)计数
incr key
incrby key increment
> set age 18 #value只能为整数
OK
> incr age
(integer) 19
> incrby age -5
(integer) 14
> incrby age 10
(integer) 24删除
del key [key ...]
> del age
(integer) 1
> get age
(nil)内部编码
- int 8个字节的长整型
- embstr 小于等于39个字节的字符串
- raw 大于39个字节的字符串
> set port 6379
OK
> object encoding port
"int"
> set hello world
OK
> object encoding hello
"embstr"
> set longString abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz
OK
> object encoding hello
"raw"
> strlen longString
(integer) 52list（列表）
list类型是用来存储多个有序的字符串。每列字符串称之为元素。一个list的最大存储为2^32-1个元素。可以对列表进行双端插入和弹出，也可以指定索引下标获取元素。
list命令
头部和尾部添加元素
lpush key value [value ...]
rpush key value [value ...]
lrange key start stop
> lpush letter "a"
(integer) 1
> lpush letter "b"
(integer) 2
> lpush letter "c"
(integer) 3
> lrange letter 0 -1
1) "c"
2) "b"
3) "a"
> rpush letter "a"
(integer) 4
> rpush letter "b"
(integer) 5
> rpush letter "c"
> lrange letter 0 -1
1) "c"
2) "b"
3) "a"
4) "a"
5) "b"
6) "c"头部和尾部弹出元素
lpop key
rpop key
> lpop letter
"c"
> lpop letter
"b"
> lrange letter 0 -1
1) "a"
2) "a"
3) "b"
4) "c"
> rpop letter
"c"
> rpop letter
"b"
> lrange letter 0 -1
1) "a"
2) "a"索引操作
索引需要对全部list进行遍历，性能会随着元素个数的增大而变差
lrange key start stop
lindex key index
ltrim key start stop
len key
> rpush letter b c
(integer) 4
> lrange letter 0 -1
1) "a"
2) "a"
3) "b"
4) "c"
> lindex letter 2
"b"
> ltrim letter 0 -2
OK
> lrange letter 0 -1
1) "a"
2) "a"
3) "b"
> llen letter
(integer) 3插入
insert key BEFORE|AFTER pivot value
> linsert letter before b c
(integer) 4
> linsert letter after a d
(integer) 5
> lrange letter 0 -1
1) "a"
2) "d"
3) "a"
4) "c"
5) "b"修改
set key index value
> lset letter 2 B
OK
> lrange letter 0 -1
1) "a"
2) "d"
3) "B"
4) "c"
5) "b"内部编码
- ziplist（压缩列表）：小于3.2版本，当元素个数小于list-max-ziplist-entries配置（默认512个），同时每个元素的值长度都小于list-max-ziplist-value配置（默认64字节）
- linkedlist（链表）：小于3.2版本，不满足ziplist的条件
- quicklist：Redis 3.2版本，以一个ziplist为节点的linkedlist
> object encoding letter
"quicklist"hash (哈希)
hash是一个string类型的field和value的映射表。 它适合用于存储对象，它是无序的，不能使用索引操作。
hash命令
设置
hset key field value
> hset user:1 name zhangSan
(integer) 1
> hset user:1 age 18
(integer) 1获取和获取所有的field-value
hget key field
hgetall key
> hget user:1 name
"zhangSan"
> hgetall user:1
1) "name"
2) "zhangSan"
3) "age"
4) "18"删除
hdel key field [field ...]
> hdel user:1 age
(integer) 1
> hdel user:2 age
(integer) 0长度
hlen key
> hlen user:1
(integer) 1批量设置
hmset key field value [field value ...]
> hmset user:2 name liSi age 23
OK
> hmget user:2 name age
1) "liSi"
2) "23"
> hlen user:1
(integer) 1
> hlen user:2
(integer) 2是否存在
hexists key field
> hexists user:2 name
(integer) 1
> hexists user:2 city
(integer) 0所有的field和所有的value
hkeys key
hvals key
> hkeys user:1
1) "name"
> hkeys user:2
1) "name"
2) "age"
> hvals user:1
1) "zhangSan"
> hvals user:2
1) "liSi"内部编码
- ziplist（压缩列表）：当元素个数小于hash-max-ziplist-entries配置（默认512个）和每个元素大小小于hash-max-ziplist-value配置（默认64字节）时
- hashtable（哈希表）：不满足ziplist条件时
> object encoding user:1
"ziplist"修改配置文件hash-max-ziplist-entries为5
> hmset test t1 v1 t2 v2 t3 v3 t4 v4 t5 v5 t6 v6
OK
> object encoding test
"hashtable"set（集合）
用来保存多个字符串元素，无序的，不能有重复元素，不能使用索引下标获取元素。一个集合可以存储2^32-1个元素。
set命令
增加
add key member [member ...]
> sadd user:1:tag it music news
(integer) 3
> sadd user:1:tag bike news
(integer) 1删除
srem key member [member ...]
> srem user:1:tag bike
(integer) 1个数
scard key
> scard user:1:tag
(integer) 3是否存在
sismember key member
> sismember user:1:tag bike
(integer) 0
> sismember user:1:tag it
(integer) 1随机返回指定个数
srandmember key [count]
> srandmember user:1:tag
"news"
> srandmember user:1:tag 3
1) "news"
2) "music"
3) "it"随机弹出
spop key [count]
> spop user:1:tag
"news"
> srandmember user:1:tag 3
1) "music"
2) "it"所有个数
smembers key
> smembers user:1:tag
1) "music"
2) "it"交集
sinter key [key ...]
> sinter user:1:tag user:2:tag
1) "music"
2) "it"并集
sunion key [key ...]
> sunion user:1:tag user:2:tag
1) "music"
2) "java"
3) "run"
4) "it"差集
sdiff key [key ...]
> sdiff user:1:tag user:2:tag
(empty list or set)
> sadd user:1:tag sleep
(integer) 1
> sdiff user:1:tag user:2:tag
1) "sleep"
> sdiff user:2:tag user:1:tag
1) "java"
2) "run"内部编码
- intset（整数集合）：元素都是整数和元素个数小于set-max-intset-entries配置（默认512个）时
- hashtable（哈希表）：不满足intset时
> object encoding user:1:tag
"hashtable"
> sadd numbers 1 2 3 4 5
(integer) 5
> object encoding numbers
"intset"zset（有序集合）
zset保证了元素不能重复，每个元素都有一个分数（score）作为排序的依据。
zset命令
添加
zadd key [NX|XX] [CH] [INCR] score member [score member ...]
> zadd books 8.2 "Redis in Action"
(integer) 1
> zadd books 9.3 "Effective Java: Second Edition : Java"
(integer) 1
> zadd books 9.1 "Think in Java"
(integer) 1
> zadd books 9.3 "Python Cookbook" 9.0 "Effective Python"
(integer) 2个数
zcard key
> zcard books
(integer) 5升序返回范围的成员
zrange key start stop [WITHSCORES]
> zrange books 0 -1
1) "Redis in Action"
2) "Effective Python"
3) "Think in Java"
4) "Effective Java: Second Edition : Java"
5) "Python Cookbook"
> zrange books 2 5
1) "Think in Java"
2) "Effective Java: Second Edition : Java"
3) "Python Cookbook"升序返回成员时带上分数
> zrange books 0 -1 withscores
1) "Redis in Action"
2) "8.1999999999999993"
3) "Effective Python"
4) "9"
5) "Think in Java"
6) "9.0999999999999996"
7) "Effective Java: Second Edition : Java"
8) "9.3000000000000007"
9) "Python Cookbook"
10) "9.3000000000000007"
> zrange books 2 5 withscores
1) "Think in Java"
2) "9.0999999999999996"
3) "Effective Java: Second Edition : Java"
4) "9.3000000000000007"
5) "Python Cookbook"
6) "9.3000000000000007"- 精度问题：内部 score 使用 double 类型进行存储，所以存在小数点精度问题
- withscores:带上分数
降序
zrevrange key start stop [WITHSCORES]
> zrevrange books 0 -1 withscores
1) "Python Cookbook"
2) "9.3000000000000007"
3) "Effective Java: Second Edition : Java"
4) "9.3000000000000007"
5) "Think in Java"
6) "9.0999999999999996"
7) "Effective Python"
8) "9"
9) "Redis in Action"
10) "8.1999999999999993"指定value的score
zscore key member
> zscore books "Think in Java"
"9.0999999999999996"根据score的数值区间升序
zrangebyscore key min max [WITHSCORES] [LIMIT offset count]
> zrangebyscore books 0 9.1 withscores
1) "Redis in Action"
2) "8.1999999999999993"
3) "Effective Python"
4) "9"
5) "Think in Java"
6) "9.0999999999999996"根据score的数值区间降序
zrevrangebyscore key max min [WITHSCORES] [LIMIT offset count]
> zrevrangebyscore books 9.1 0 withscores
1) "Think in Java"
2) "9.0999999999999996"
3) "Effective Python"
4) "9"
5) "Redis in Action"
6) "8.1999999999999993"根据score的数值降序输出所有元素
> zrevrangebyscore books +inf -inf withscores
1) "Python Cookbook"
2) "9.3000000000000007"
3) "Effective Java: Second Edition : Java"
4) "9.3000000000000007"
5) "Think in Java"
6) "9.0999999999999996"
7) "Effective Python"
8) "9"
9) "Redis in Action"
10) "8.1999999999999993"- +inf 正无穷
- -inf 负无穷
删除
zrem key member [member ...]
> zrem books "Effective Java: Second Edition : Java"
(integer) 1增加分数
zincrby key increment member
> zincrby books 2 "Redis in Action"
"10.199999999999999"
> zincrby books -1 "Redis in Action"
"9.1999999999999993"交集
zinterstore destination numkeys key [key ...] [WEIGHTS weight] [AGGREGATE
> zadd textbooks 8 "chinese" 9 "english" 9.5 "mathematics"
(integer) 3
> zadd textbooks 9.2 "Think in Java"
(integer) 1
> zrange books 0 -1
1) "Redis in Action"
2) "Effective Python"
3) "Think in Java"
4) "Python Cookbook"
> zrange textbooks 0 -1
1) "chinese"
2) "english"
3) "Think in Java"
4) "mathematics"
> zinterstore newbooks 2 books textbooks
(integer) 1
> zrange newbooks 0 -1
1) "Think in Java"并集
zunionstore destination numkeys key [key ...] [WEIGHTS weight] [AGGREGATE
> zunionstore newUnionbooks 2 books textbooks
(integer) 7
> zrange newUnionbooks 0 -1
1) "chinese"
2) "Redis in Action"
3) "Effective Python"
4) "english"
5) "Python Cookbook"
6) "mathematics"
7) "Think in Java"内部编码
- ziplist（压缩列表）：元素个数小于zset-max-ziplist-entries配置（默认128个）和元素长度小于zset-max-ziplist-value配置（默认64B）时
- skiplist（跳跃表）：不满足ziplist时
> object encoding books
"ziplist"结语
本人深知水平有限，欢迎指正本文错误之处。
参考资料
《Redis 实战》
《Redis 开发与运维》
《Redis 深度历险：核心原理与应用实践》