Caching TTL for @Cacheable annotation

Setting Cache TTL in Spring Boot

Spring's @Cacheable doesn't directly support TTL. You manage TTL indirectly using CacheEviction. Several strategies exist:

1. Using @Scheduled for periodic eviction:

This approach evicts cached entries after a fixed time. Define a @Scheduled task to remove entries based on entry creation time (e.g., using a custom key).

@Scheduled(fixedRate = 3600000) // Evict every hour
public void evictExpiredEntries() {
    // Logic to find and evict entries older than 1 hour
    // Requires storing creation timestamp within cache key or value
}

2. Custom Cache Manager with Expiring Cache:

Create a custom CacheManager implementing Cache with expiration logic. This offers more fine-grained control.

public class ExpiringCache implements Cache {
    // ... (Implementation with expiry logic using java.util.concurrent.ConcurrentHashMap) ...
}

Register this custom CacheManager in your Spring configuration.

3. Using a dedicated caching library:

Libraries like Caffeine offer built-in TTL functionality. Integrate this library with Spring's caching abstraction. This is often the simplest and most efficient approach.

Example (Caffeine):

@Configuration
public class CacheConfig {
    @Bean
    public CaffeineCache caffeineCache() {
        return CaffeineCacheBuilder.newBuilder()
                .maximumSize(1000)
                .expireAfterWrite(3600, TimeUnit.SECONDS) // 1 hour TTL
                .build();
    }
}

Choose the method best suited to your needs. For simple scenarios, @Scheduled with careful key design suffices. Complex requirements benefit from a custom cache manager or dedicated libraries like Caffeine for superior performance and features. Remember to adjust fixedRate and expireAfterWrite values according to your specific TTL needs.