lucasfroque/spring-boot-cache-example

In this project i am going to show a example how to use the Caching in Spring and generally improve the performance of our system.

💻 Built with

Technologies used in the project:

Java
Springboot
SpringData JPA
Spring Cache
Lombok

🚀 Getting started

Add the spring cache dependency

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-cache</artifactId>
</dependency>

Enabling cache

@SpringBootApplication
@EnableCaching
public class SpringBootCacheExampleApplication {

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

}

Implementing the cache

for that we need to use some @Annotations

These are:

@Cacheable - to cache the result of the method
@CacheEvict - to evict the cache
@Caching - to group the @Cacheable and @CacheEvict annotations

@Service
public class UserServiceImpl implements UserService {

    public static final Logger logger = LoggerFactory.getLogger(UserServiceImpl.class);

    @Autowired
    private UserRepository repository;

    @Override
    @CacheEvict(value = "users", allEntries = true)
    public User save(User user) {
        logger.info("Saving user: {}", user.getName());
        return repository.save(user);
    }

    @Override
    @Caching(evict = {
            @CacheEvict(value = "users", allEntries = true),
            @CacheEvict(value = "user", key = "#user.id")
    })
    public User update(Long id, User user) {
        User userToUpdate = repository.findById(id).get();
            userToUpdate.setName(user.getName());
            userToUpdate.setEmail(user.getEmail());

            logger.info("Updating user: {}", userToUpdate.getName());
            return repository.save(userToUpdate);
    }

    @Override
    @Cacheable(value = "users")
    public List<User> findAll() {
        logger.info("Finding all users");
        return repository.findAll();
    }

    @Override
    @Cacheable(value = "user", key = "#id", unless = "#result == null")
    public User findById(Long id) {
        logger.info("Finding user by id: {}", id);
        return repository.findById(id).orElse(null);
    }

    @Override
    @Caching(evict = {
            @CacheEvict(value = "users", allEntries = true),
            @CacheEvict(value = "user", key = "#id")
    })
    public void delete(Long id) {
        logger.info("Deleting user by id: {}", id);
        repository.deleteById(id);
    }
}

Testing the cache

Running the application

mvn clean install

mvn spring-boot:run

send a request to the application

GET localhost:8080/users to get all users
GET localhost:8080/users/1 to get user by id
PUT localhost:8080/users/1 to update user by id
POST localhost:8080/users to save user
DELETE localhost:8080/users/1 to delete user by id

Check the logs

For the first request if nothing is cached we have the following logs:

curl -X GET localhost:8080/users

LOGS:
INFO 1034 --- [nio-8080-exec-2] c.l.s.service.impl.UserServiceImpl       : Finding all users

For the second request if something is cached we don't have any logs:

curl -X GET localhost:8080/users

LOGS:

But if we delete some user we have the following logs:

curl -X DELETE localhost:8080/users/1

LOGS:
INFO 1034 --- [nio-8080-exec-8] c.l.s.service.impl.UserServiceImpl       : Deleting user by id: 1

Then will be deleted the cache for the user with id 1 and for the list of users.

And if we try to list the users again we have the following logs:

curl -X GET localhost:8080/users

LOGS:
INFO 1034 --- [nio-8080-exec-2] c.l.s.service.impl.UserServiceImpl       : Finding all users

To learn more about the spring cache visit:

https://docs.spring.io/spring-framework/docs/3.2.x/spring-framework-reference/html/cache.html

https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/cache/annotation/Cacheable.html#:%7E:text=Annotation%20Type%20Cacheable&text=Annotation%20indicating%20that%20the%20result,invoked%20for%20the%20given%20arguments

lucasfroque / spring-boot-cache-example