@Transactional with Spring Data MongoDB
Guide to utilise @Transactional with Spring Data MongoDB.
Background
Unlike Spring Data JPA, Spring Data MongoDB does not support @Transactional out of the box. In this guide, we will explore how to implement @Transactional with Spring Data MongoDB.
Scenario
We will implement based on the following scenario:
When a new User is created
Then the status should be ACTIVEImplementation
Integration Test
We will verify our implementation through integration test whereby we will create a new User and verify that the status is ACTIVE.
@AutoConfigureRestTestClient
@SpringBootTest(webEnvironment = RANDOM_PORT)
@Testcontainers
class CreateUserTests {
@Container
@ServiceConnection
private static final MongoDBContainer mongo = new MongoDBContainer("mongo:latest").withReplicaSet();
@Autowired
private RestTestClient restTemplate;
@Test
void create() {
var body = """
{
"username": "rashidi.zin",
"name": "Rashidi Zin"
}
""";
restTemplate.post().uri("/users")
.contentType(APPLICATION_JSON)
.body(body)
.exchange()
.expectStatus().isCreated()
.expectBody()
.jsonPath("$.status").isEqualTo("ACTIVE");
}
}Event Listener
We will start by implementing an EventListener that will be responsible to assign the status to ACTIVE when a new User is created.
@Component
class UpdateUserStatus {
@TransactionalEventListener
public void onBeforeSave(BeforeSaveEvent<User> event) {
var user = event.getSource();
user.status(ACTIVE);
}
}As we can see, onBeforeSave is annotated with @TransactionalEventListener. This annotation will ensure that the event listener will be
executed within a transaction.
Transactional Method
Next, we will implement a transactional method that will create a new User.
@RestController
class UserResource {
private final UserRepository repository;
UserResource(UserRepository repository) {
this.repository = repository;
}
@PostMapping("/users")
@ResponseStatus(CREATED)
@Transactional
public User add(@RequestBody User user) {
return repository.save(user);
}
}Configuration Class
Finally, we will configure MongoTransactionManager to enable transaction support for MongoDB.
@Configuration
@EnableTransactionManagement
class MongoTransactionManagerConfiguration {
@Bean
public PlatformTransactionManager transactionManager(MongoDatabaseFactory factory) {
return new MongoTransactionManager(factory);
}
}Verification
In order to ensure that our implementation is working as expected, the test implemented in CreateUserTests should pass.