Spring Caching

Spring Caching — a framework feature that allows you to store method results in cache to improve performance and reduce database or computation load.

🧩 Purpose

When a cached method is called with the same parameters again, Spring returns the cached result instead of executing the method.

Basic Example:

@Service
public class UserService {

    @Cacheable("users")
    public User getUserById(Long id) {
        System.out.println("Fetching from DB...");
        return userRepository.findById(id).orElseThrow();
    }
}

@Service
public class UserService {

    @Cacheable("users")
    public User getUserById(Long id) {
        System.out.println("Fetching from DB...");
        return userRepository.findById(id).orElseThrow();
    }
}

✅ On first call → runs the method and caches the result.
✅ On next calls with same id → returns cached result directly.

🧠 Key Annotations

• @EnableCaching → activates caching in Spring Boot.
• @Cacheable → caches method result.
• @CachePut → updates cache with new value.
• @CacheEvict → removes data from cache.

Configuration Example:

@SpringBootApplication
@EnableCaching
public class App { }

@SpringBootApplication
@EnableCaching
public class App { }

Spring Boot supports cache providers like ConcurrentMap, Ehcache, Caffeine, Redis, etc.