Unlocking Redis: 16 Real-World Use Cases to Supercharge Your Applications

1. Cache

String type. Example: hot data cache (e.g., reports, trending topics), object cache, full-page cache, which can improve access to hot data.

2. Distributed Data Sharing

String type, because Redis is a distributed independent service that can be shared among multiple applications.

Example: distributed session.

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

3. Distributed Lock

String type setnx method, succeeds only when the key does not exist, returns true.

<code>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);
}
</code>

4. Global ID

int type, incrby, using atomicity. Example: incrby userid 1000. Used in sharding scenarios to obtain a range of IDs.

5. Counter

int type, incr method. Example: article view count, Weibo likes, allowing some delay by writing to Redis first and syncing to DB later.

6. Rate Limiting

int type, incr method. Use visitor IP as key; each request increments the count, and exceeding the limit returns false.

7. Bit Statistics

String type bitcount (bitmap data structure). Characters are stored as 8‑bit binary.

<code>set k1 a
setbit k1 6 1
setbit k1 7 0
get k1
/* 6 7 represent the binary bits of 'a'
   ASCII of 'a' is 97 -> 01100001
   ASCII of 'b' is 98 -> 01100010
   Bitmaps are space‑efficient (1 MB = 8 388 608 bits) and suitable for large‑scale statistics. */
</code>

Examples: online user statistics, retention statistics.

<code>setbit onlineusers 01
setbit onlineusers 11
setbit onlineusers 20
</code>

Supports bitwise AND, OR, XOR, NOT operations.

<code>BITOPAND destkey key1 key2 ...
BITOPOR destkey key1 key2 ...
BITOPXOR destkey key1 key2 ...
BITOPNOT destkey key
</code>

Calculate users online for 7 consecutive days:

<code>BITOP "AND" "7_days_both_online_users" "day_1_online_users" "day_2_online_users" ... "day_7_online_users"
</code>

8. Shopping Cart

String or hash. All operations possible on strings are also possible on hashes.

key: user id; field: product id; value: quantity.

+1: hincr; -1: hdecr; delete: hdel; get all: hgetall; count: hlen.

9. User Timeline

List (doubly linked list) can be used directly as a timeline; insertion maintains order.

10. Message Queue

List provides two blocking pop operations: blpop and brpop, which can set a timeout.

blpop key timeout – removes and returns the first element, blocking until timeout or element appears.

brpop key timeout – removes and returns the last element, blocking similarly.

These correspond to Java's blocking queue semantics (FIFO for queue, LIFO for stack).

11. Lottery

Randomly obtain a value.

<code>spop myset
</code>

12. Likes, Check‑in, Clock‑in

Use a set like

like:t1001

to maintain all users who liked a specific post.

sadd like:t1001 u3001 – like

srem like:t1001 u3001 – unlike

sismember like:t1001 u3001 – check like

smembers like:t1001 – list all likers

scard like:t1001 – count likes

This is simpler than using a relational database.

13. Product Tags

Maintain product tags with sets, e.g.,

tags:i5001

.

sadd tags:i5001 "Clear screen"

sadd tags:i5001 "True color display"

sadd tags:i5001 "Excellent workflow"

14. Product Filtering

Use set operations to get differences, intersections, unions.

<code>sdiff set1 set2
sinter set1 set2
sunion set1 set2
</code>

Example: add product attributes.

<code>sadd brand:apple iPhone11
sadd brand:ios iPhone11
sad screensize:6.0-6.24 iPhone11
sad screentype:lcd iPhone11
</code>

Filter products that are Apple, iOS, screen size 6.0‑6.24, and LCD:

<code>sinter brand:apple brand:ios screensize:6.0-6.24 screentype:lcd
</code>

15. Follow & Recommendation Model

Use sets to represent follow and fan relationships.

sadd 1:follow 2

sadd 2:fans 1

sadd 1:fans 2

sadd 2:follow 1

Mutual follows (intersection):

<code>sinter 1:follow 2:fans
</code>

Potential acquaintances (difference):

<code>sdiff 2:follow 1:follow
sdiff 1:follow 2:follow
</code>

16. Ranking

Increment news click count:

<code>zincrby hotNews:20190926 1 n6001
</code>

Get top 15 items of today:

<code>zrevrange hotNews:20190926 0 15 withscores
</code>