How to Use Caffeine Cache in Spring Boot: Simple Guide

To use Caffeine Cache in Spring Boot, add the spring-boot-starter-cache and caffeine dependencies, enable caching with @EnableCaching, and configure a CaffeineCacheManager. Then annotate methods with @Cacheable to cache their results automatically.

Syntax

Here is the basic setup to use Caffeine cache in Spring Boot:

• Add dependencies for Spring Cache and Caffeine.
• Enable caching in your main application class with @EnableCaching.
• Configure a CaffeineCacheManager bean to customize cache settings.
• Use @Cacheable on methods whose results you want to cache.

java

import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.caffeine.CaffeineCacheManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import com.github.benmanes.caffeine.cache.Caffeine;

@Configuration
@EnableCaching
public class CacheConfig {

    @Bean
    public CaffeineCacheManager cacheManager() {
        CaffeineCacheManager cacheManager = new CaffeineCacheManager("items");
        cacheManager.setCaffeine(Caffeine.newBuilder()
            .initialCapacity(100)
            .maximumSize(500)
            .expireAfterWrite(java.time.Duration.ofMinutes(10)));
        return cacheManager;
    }
}

Example

This example shows a Spring Boot service caching method results using Caffeine. The getItemById method caches its return value for 10 minutes. The first call fetches data normally; subsequent calls return cached data instantly.

java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;

@SpringBootApplication
public class CaffeineCacheApplication {
    public static void main(String[] args) {
        SpringApplication.run(CaffeineCacheApplication.class, args);
    }
}

@Service
class ItemService {

    @Cacheable("items")
    public String getItemById(String id) {
        simulateSlowService();
        return "Item-" + id;
    }

    private void simulateSlowService() {
        try {
            Thread.sleep(3000); // Simulate delay
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }
    }
}

Output

First call to getItemById("123") takes ~3 seconds and returns "Item-123".
Subsequent calls to getItemById("123") return instantly with cached "Item-123".

Common Pitfalls

• Forgetting to add @EnableCaching disables caching.
• Not configuring CaffeineCacheManager leads to default cache with no expiration.
• Using inconsistent cache names between configuration and @Cacheable causes cache misses.
• Caching methods with side effects or mutable return values can cause unexpected behavior.

java

/* Wrong: Missing @EnableCaching disables caching */
@SpringBootApplication
public class App {
    public static void main(String[] args) {
        SpringApplication.run(App.class, args);
    }
}

/* Right: Add @EnableCaching to enable caching */
@SpringBootApplication
@EnableCaching
public class App {
    public static void main(String[] args) {
        SpringApplication.run(App.class, args);
    }
}

Quick Reference

Summary tips for using Caffeine cache in Spring Boot:

• Add spring-boot-starter-cache and com.github.ben-manes.caffeine dependencies.
• Enable caching with @EnableCaching.
• Configure CaffeineCacheManager bean for cache size and expiry.
• Use @Cacheable on methods to cache results.
• Ensure cache names match between config and annotations.

Key Takeaways

Add Caffeine and Spring Cache dependencies and enable caching with @EnableCaching.

Configure CaffeineCacheManager bean to control cache size and expiration.

Use @Cacheable on methods to cache their return values automatically.

Ensure cache names are consistent between configuration and annotations.

Avoid caching methods with side effects or mutable return values.