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Yyds dry goods inventory tells us 16 common usage scenarios of redis at one go

2022-06-24 23:27:00 【Ma Nong Xiao Song】

Catalog

cache
Data sharing distributed
Distributed lock
overall situation ID
Counter
Current limiting
Bit Statistics
The shopping cart
User message timeline timeline
Message queue
Luck draw
give the thumbs-up 、 Sign in 、 Clock in
Product label
Product selection
User attention 、 Recommended model
Ranking List

1、 cache

String Types such as ： Hot data cache （ For example, report 、 Star cheating ）, Object caching 、 Full page caching 、 Can improve access to hotspot data .

2、 Data sharing distributed

String type , because Redis It's a distributed, stand-alone service , Can be shared between multiple applications, for example ： Distributed Session

       
       <
       
       dependency
       
       > 
       
       <
       
       groupId
       
       >org.springframework.session
       
       </
       
       groupId
       
       > 
       
       <
       
       artifactId
       
       >spring-session-data-redis
       
       </
       
       artifactId
       
       > 
       
       </
       
       dependency
       
       >
      
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3、 Distributed lock

String type setnx Method , Only when it doesn't exist can it be added successfully , return true

       
       public 
       
       static 
       
       boolean 
       
       getLock(
       
       String 
       
       key) {
       
       Long 
       
       flag 
       
       = 
       
       jedis.
       
       setnx(
       
       key, 
       
       "1");
       
       if (
       
       flag 
       
       == 
       
       1) {
       
       jedis.
       
       expire(
       
       key, 
       
       10);
       
    }
       
       return 
       
       flag 
       
       == 
       
       1;
       
}
       
       public 
       
       static 
       
       void 
       
       releaseLock(
       
       String 
       
       key) {
       
       jedis.
       
       del(
       
       key);
       
}
      
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4、 overall situation ID

int type ,incrby, Using atomicity

incrby userid 1000

The scene of sub database and sub table , Take one piece at a time

5、 Counter

int type ,incr Method

for example ： The amount of reading 、 Microblog likes 、 Allow a certain delay , Write... First Redis Then synchronize to the database regularly

6、 Current limiting

int type ,incr Method takes the visitor's ip And other information as key, Add one count at a time , If it exceeds the number of times, it will return false

7、 Bit Statistics

String Type of bitcount（1.6.6 Of bitmap Data structure introduction ）

The characters are written with 8 Bit binary storage

      
      
       
       set k1 a
       
       
setbit k1 6 1
       
       
setbit k1 7 0
       
       
get k1 
       
       
/* 6 7  Representative a Modification of binary bits 
       
       
a  Corresponding ASCII Code is 97, Converting to binary data is 01100001
       
       
b  Corresponding ASCII Code is 98, Converting to binary data is 01100010
       
       

       
       
 because bit Very space saving （1 MB=8388608 bit）, It can be used for statistics of large amount of data .
       
       
*/
      
      
      
      
       
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for example ： Online user statistics , Retain user statistics

      
      
       
       setbit onlineusers 01 
       
       
setbit onlineusers 11 
       
       
setbit onlineusers 20
      
      
      
      
       
       1.
       
       2.
       
       3.

Support bitwise and 、 Bitwise OR etc

      
      
       
       BITOPANDdestkeykey[key...] , To one or more  key  Seek logic and , And save the result to  destkey .       
       
       
BITOPORdestkeykey[key...] , To one or more  key  Seek logic or , And save the result to  destkey . 
       
       
BITOPXORdestkeykey[key...] , To one or more  key  Seek logical XOR , And save the result to  destkey . 
       
       
BITOPNOTdestkeykey , For given  key  Logic is not , And save the result to  destkey .
      
      
      
      
       
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To calculate the 7 Tiandu online users

      
      
       
       BITOP "AND" "7_days_both_online_users" "day_1_online_users" "day_2_online_users" ...  "day_7_online_users"
      
      
      
      
       
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8、 The shopping cart

String or hash. all String What can be done hash You can do it. #yyds Dry inventory # Say in one breath Redis 16 Three common use scenarios _redis

key： user id;field： goods id;value： The number .
+1：hincr.-1：hdecr. Delete ：hdel. Future generations ：hgetall. Number of goods ：hlen.

9、 User message timeline timeline

list, Double linked list , Act directly as timeline Just fine . Insert in order

10、 Message queue

List Two blocked pop-up operations are provided ：blpop/brpop, Timeout can be set

blpop：blpop key1 timeout Remove and get the first element of the list , If there are no elements in the list, it will block the list until the wait timeout or pop-up elements are found .
brpop：brpop key1 timeout Remove and get the last element of the list , If there are no elements in the list, it will block the list until the wait timeout or pop-up elements are found .

Operation above . In fact, that is java Blocking queue . The more you learn . The lower the cost of learning

queue ： First in, first out ：rpush blpop, Left head right tail , Right into the queue , Queue left
Stack ： First in, then out ：rpush brpop

11、 Luck draw

With a random value

12、 give the thumbs-up 、 Sign in 、 Clock in

#yyds Dry inventory # Say in one breath Redis 16 Three common use scenarios _iphone_02 If the microblog above ID yes t1001, user ID yes u3001 use like:t1001 To maintain the t1001 All the like users of this microblog

I like this microblog ：sadd like:t1001 u3001
Cancel likes ：srem like:t1001 u3001
Do you like it ：sismember like:t1001 u3001
All users who like ：smembers like:t1001
Number of likes ：scard like:t1001

Is it much simpler than the database .

13、 Product label

#yyds Dry inventory # Say in one breath Redis 16 Three common use scenarios _redis_03 Old rules , use tags:i5001 To maintain all labels on the product .

sadd tags:i5001 The picture is clear and delicate
sadd tags:i5001 True color clear screen
sadd tags:i5001 The process is extremely

14、 Product selection

      
      
       
       //  Get the difference set 
       
       
sdiff set1 set2
       
       
//  Get intersection （intersection ）
       
       
sinter set1 set2
       
       
//  Get Union 
       
       
sunion set1 set2
      
      
      
      
       
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       2.
       
       3.
       
       4.
       
       5.
       
       6.

#yyds Dry inventory # Say in one breath Redis 16 Three common use scenarios _redis_04 If ：iPhone11 Listed on the

      
      
       
       sadd brand:apple iPhone11
       
       

       
       
sadd brand:ios iPhone11
       
       

       
       
sad screensize:6.0-6.24 iPhone11
       
       

       
       
sad screentype:lcd iPhone 11
      
      
      
      
       
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Competition goods , Apple 、ios Of 、 Screen in 6.0-6.24 Between , The screen material is LCD The screen

      
      
       
       sinter brand:apple brand:ios screensize:6.0-6.24 screentype:lcd
      
      
      
      
       
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15、 User attention 、 Recommended model

follow Focus on fans Fans pay attention to each other ：

sadd 1:follow 2
sadd 2:fans 1
sadd 1:fans 2
sadd 2:follow 1

The people I'm concerned about are paying attention to him ( intersect )：

sinter 1:follow 2:fans

People you may know ：

user 1 People you may know ( Difference set )：sdiff 2:follow 1:follow
user 2 People you may know ：sdiff 1:follow 2:follow

16、 Ranking List

id by 6001 The number of news hits plus 1：

      
      
       
       zincrby hotNews:20190926 1 n6001
      
      
      
      
       
       1.

Get the most hits today 15 strip ：

      
      
       
       zrevrange hotNews:20190926 0 15 withscores
      
      
      
      
       
       1.

#yyds Dry inventory # Say in one breath Redis 16 Three common use scenarios _ cache _05

      
      
       
        Address ：https://blog.csdn.net/weixin_43878826/article/details/119461093
      
      
      
      
       
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