To implement caching in the service layer using Spring's `@Cacheable` annotation, follow these steps: 1. **Enable Caching in Spring Boot**: First, make sure you have the caching dependencies in your `pom.xml`: ```xml org.springframework.boot spring-boot-starter-data-redis org.springframework.boot spring-boot-starter-cache ``` 2. **Configure Redis**: Add the following configuration properties to your `application.properties`: ```properties spring.redis.host=localhost spring.redis.port=6379 spring.cache.type=redis ``` 3. **Enable Caching in Application**: Add the `@EnableCaching` annotation to your main application class: ```java @SpringBootApplication @EnableCaching public class FileSharingPlatformApplication { public static void main(String[] args) { SpringApplication.run(FileSharingPlatformApplication.class, args); } } ``` 4. **Implement Caching in Service Layer**: Use the `@Cacheable` annotation in your service methods to cache frequently accessed data. For example, in your `UserService`: ```java @Service public class UserServiceImpl implements UserService { @Autowired private UserRepository userRepository; @Cacheable(value = "userMetadata", key = "#id") public User getUserMetadata(Long id) { return userRepository.findById(id).orElseThrow(); } } ``` 5. **Understand Caching Behavior**: - The `@Cacheable` annotation will store the method's return value in the cache with the specified key - Subsequent calls with the same parameters will return the cached value instead of executing the method - Use `@CachePut` for methods that update data and should update the cache - Use `@CacheEvict` for methods that invalidate cached data 6. **Consider Cache Invalidation**: Implement a strategy to invalidate cached data when underlying data changes. For example: ```java @CachePut(value = "userMetadata", key = "#user.id") public User updateUser(User user) { return userRepository.save(user); } ``` Next steps: 1. Implement caching for file metadata using similar approach 2. Configure cache expiration if needed 3. Monitor cache performance using Redis client or Spring Boot Actuator Further reading: - [Spring Documentation - Caching](https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#features.caching) - [Redis Documentation](https://redis.io/docs)