Common Redis Use Cases and Implementation Patterns

Author "架构君" shares a collection of practical Redis usage scenarios, illustrating how different Redis data structures and commands can solve common application problems.

1. Caching

Uses String type for hot data such as reports, object caches, and full-page caches to improve access speed.

2. Distributed Data Sharing

Leverages Redis as a distributed service to share data across applications, e.g., distributed sessions.

<dependency>
  <groupId>org.springframework.session</groupId>
  <artifactId>spring-session-data-redis</artifactId>
</dependency>

3. Distributed Lock

Implements a lock using SETNX which succeeds only when the key does not exist.

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);
}

4. Global ID

Uses INCRBY on an int key to generate atomic incremental IDs, suitable for sharding scenarios.

5. Counter

Employs INCR for counting events such as article views or likes, allowing asynchronous persistence to a database.

6. Rate Limiting

Counts accesses per IP (or other identifier) with INCR ; if the count exceeds a threshold, further requests are rejected.

7. Bit Statistics

Uses bitmap commands like BITCOUNT and SETBIT to store and analyze binary data efficiently, e.g., online user statistics.

set k1 a
setbit k1 6 1
setbit k1 7 0
get k1

8. Shopping Cart

Models a cart with String or Hash ; key is user ID, field is product ID, value is quantity. Operations use HINCRBY , HDEL , HGETALL , etc.

9. User Timeline

Implements a timeline using a List (doubly linked list) where new entries are inserted in order.

10. Message Queue

Uses List blocking pop commands BLPOP and BRPOP with timeout to build a simple message queue.

11. Lottery

Randomly selects a member from a set using SPOP .

spop myset

12. Likes / Check‑in / Clock‑in

Manages likes with sets: SADD like:postId userId , SREM to cancel, SISMEMBER to check, SCARD for count.

13. Product Tags

Stores tags in a set, e.g., SADD tags:i5001 "High definition screen" .

14. Product Filtering

Combines sets using SINTER , SUNION , SDIFF to filter products by brand, OS, screen size, etc.

sinter brand:apple brand:ios screensize:6.0-6.24 screentype:lcd

15. Follow / Recommendation Model

Tracks follows and fans with sets; intersections and differences reveal mutual follows and potential connections.

16. Leaderboard

Uses sorted sets: ZINCRBY hotNews:20190926 1 n6001 to increment score, ZREVRANGE hotNews:20190926 0 15 WITHSCORES to retrieve top items.

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