I have a very basic Spring Boot/JPA stack app, with a controller, service layer, and repository that does not persist updates as I understand it should.
A trivial Entity:
#Entity
public class Customer {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private Long id;
private String name;
protected Customer() {}
public Customer(String name) { this.name = name; }
// standard getters,setters //
}
A trivial Repository:
#Repository
public interface CustomerRepository extends CrudRepository<Customer, Long> {}
A simple Service layer:
// If the service is #Transactional and the controller is not, the update does NOT occur
#Transactional
#Service
public class CustomerService {
private static final Logger LOG = getLogger(CustomerService.class);
#Autowired
private CustomerRepository customerRepository;
boolean updateCustomerName(Long id, String name) {
Customer customer = customerRepository.findOne(id);
if (customer == null) { return false; }
// Modifies the entity
customer.setName(name);
// No explicit save()
return true;
}
}
And a REST controller that uses it all:
// If the controller is #Transactional and the service is not, the update occurs
#RestController
#RequestMapping("/mvc")
public class CustomerController {
#Autowired
private CustomerService customerService;
#RequestMapping(path = "{id}", method = RequestMethod.PUT)
public ResponseEntity updateCustomerName(#PathVariable Long id, #RequestParam("name") String name) {
customerService.updateCustomerName(id,name);
return ResponseEntity.noContent().build();
}
}
These are wired together with a simple one-liner SpringBootApplication
I have SQL debug logs enabled and see the selects, update, etc.
With the code above: When the service method is invoked by the controller, the modified entity is not persisted. SQL logs show the select of the entity but no update.
There is also no update if nothing is marked #Transactional
However, simply by moving the #Transactional annotation from the service class to the controller class, the SQL update does occur.
If I add an explicit customerRepository.save(customer) to the service method, the update also occurs. But my understanding is that the ORM should automatically save modified persistent entities.
I'm sure the issue has something to do with the EntityManager lifecycle in the web request, but I'm puzzled. Do I need to do additional configuration?
Complete example at https://github.com/monztech/SO-41515160
EDIT: This was solved, see below. Per the Spring spec #Transactional does not work in package-private methods and mistakenly did not make the update service method public.
The update will occur if the method is public and the service class has the #Transactional annotation.
I do have another question, however. Why is the #Transactional annotation necessary? (the update does not occur without it) Shouldn't the entity manager still persist the object because of the open session in view mechanism that Spring uses, independent of any transaction?
Make your updateCustomerName method public.
Related
I have a parent transaction at controller layer, but I want to start a new transaction when I call a repository, to achieve this I tried annotating Repository interface as below
#Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRES_NEW)
public interface EventRepo extends JpaRepository<Event, Integer>{ }
However this seems to not start a new transaction upon calls to EventRepo#save. Why?
Here is my service layer.
public interface IApplicationService {
void save(Event event);
}
#Service
public class ApplicationService implements IApplicationService {
#Autowired
private EventRepo eventRepo;
#Override
public void save(Event event) {
eventRepo.save(event);
}
}
It is in turn called from controller layer
#RequestMapping(value="/{indicator}", method=RequestMethod.POST)
#Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRES_NEW)
#ResponseBody
public String processRequest(#PathVariable Integer indicator) {
Event event = new Event("Student1");
service.save(event);
if(indicator != 0) {
throw new RuntimeException();
}
return "Success";
}
However everything works perfectly if I annotate Service interface with #Transactional
#Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRES_NEW)
public interface IApplicationService {
void save(Event event);
}
When I say working what is mean is, if I run the below curl commands I will see 2 rows in h2 db for Event entity
curl -X POST http://localhost:8080/1
curl -X POST http://localhost:8080/0
I understand it is good to control transactions at Service layer then repository or controller layer, constructing situation this way makes it easy to demonstrate the problem.
Spring boot starter version is 2.5.6
below dependencie have versions managed by springboot starter
spring-boot-starter-data-jpa
spring-boot-starter-web
lombok
h2
Here is a thread that suggests it should be ok to annotate Repository layer although discourages it.
#Transactional on a JpaRepository
In this Spring article we can read the following:
Additionally, we can get rid of the #Transactional annotation for the method as the CRUD methods of the Spring Data JPA repository implementation are already annotated with #Transactional.
To me, this means that whatever #Transactional annotation you add to your EventRepo will be overridden by the #Transactional annotation mentioned above in the CRUD methods. Having said that, I really doubt #Transactional annotation has any effect in JpaRepository methods. It would have in your own custom methods, but it seems to me that it has none in the inherited methods.
In order to apply your own transactional settings in EventRepo#save override the save method:
#Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRES_NEW)
public interface EventRepo extends JpaRepository<Event, Integer>{
#Override
Event save(Event event);
}
Explanation
Spring ignores your #Transactional annotation because it cannot find the save method in the EventRepo proxy and applies the default transaction settings from the parent CrudRepository interface.
Further reading: How Does Spring #Transactional Really Work?
Given the following workflow in a Spring Boot application:
A RestController receives a request to update the User entity.
The controller delegates the updating to a UserService.
The UserService needs to call an external system which updates the User object on the same database instance. We're dealing with a legacy system here, so we need to stick to this fact.
The UserService needs to save the updated User.
I'm aware of the problem that #4 won't work as #3 has already updated the object.
#RestController
#RequestMapping("/api/user")
#RequiredArgsConstructor
public class UserController {
private final UserService userService;
private final ExternalService externalService;
#PutMapping
public ResponseEntity<UserResponse> createOrUpdateBewerberdaten(#RequestBody #Valid UserRequest userRequest) {
UserResponse userResponse = userService.update(userRequest);
return ResponseEntity.ok(userResponse);
}
#Service
#RequiredArgsConstructor
public class UserService {
private final UserRepository userRepository;
private final ExternalService externalService;
#Transactional
public UserResponse update(UserRequest userRequest) {
User user = userRepository.findById(userRequest.getId());
user.setEmail(userRequest.getEmail());
// this calls an external system via REST updating the user on the same database instance
externalService.update(user);
// this won't work as the user has been updated by externalService
userRepository.save(user)
return new UserResponse(user);
}
}
Is there some pattern I could apply to get the latest version of the User object? My current approach is to call the ExternalService from the controller and put #4 in a dedicated public method, which is also annotated with #Transactional. However this feels like bloating the controller which I would like to keep as simple as possible.
I try to understand why this code doesn't work
In component:
#PostConstruct
public void runAtStart(){
testStream();
}
#Transactional(readOnly = true)
public void testStream(){
try(Stream<Person> top10ByFirstName = personRepository.findTop10ByFirstName("Tom")){
top10ByFirstName.forEach(System.out::println);
}
}
And repository :
public interface PersonRepository extends JpaRepository<Person, Long> {
Stream<Person> findTop10ByFirstName(String firstName);
}
I get:
org.springframework.dao.InvalidDataAccessApiUsageException: You're trying to execute a streaming query method without a surrounding transaction that keeps the connection open so that the Stream can actually be consumed. Make sure the code consuming the stream uses #Transactional or any other way of declaring a (read-only) transaction.
One key thing about Spring is that many annotated features use proxies to provide the annotation functionality. That is #Transactional, #Cacheable and #Async all rely on Spring detecting those annotations and wrapping those beans in a proxy bean.
That being the case, a proxied method can only be used when invoked on the class and not from within the class. See this about the topic.
Try:
Refactoring and call this #Transactional method from another class in your context, or
By self-autowiring the class into itself and calling the #Transactional method that way.
To demonstrate (1):
public class MyOtherClass {
#Autowired
private MyTestStreamClass myTestStreamClass;
#PostConstruct
public void runAtStart(){
// This will invoke the proxied interceptors for `#Transactional`
myTestStreamClass.testStream();
}
}
To demonstrate (2):
#Component
public class MyTestStreamClass {
#Autowired
private MyTestStreamClass myTestStreamClass;
#PostConstruct
public void runAtStart(){
// This will invoke the proxied interceptors for `#Transactional` since it's self-autowired
myTestStreamClass.testStream();
}
#Transactional(readOnly = true)
public void testStream(){
try(Stream<Person> top10ByFirstName = personRepository.findTop10ByFirstName("Tom")){
top10ByFirstName.forEach(System.out::println);
}
}
}
I have rest style controller in Spring. In controller I have injected dao interfaces. From controller I persist data. In the other words, I have like REST web service. people sends me data, and I persits it.
/**
* Payment rest controller which receives
* JSON of data
*/
#Controller
#RequestMapping("/data")
public class PaymentTransaction {
#Autowired
private TestDao dao;
#RequestMapping(value = "/test", method = RequestMethod.POST)
#ResponseBody()
public String test(HttpServletRequest request) {
...
}
At the moment I have #transaction annotation in Dao classes. For instance:
import org.springframework.transaction.annotation.Transactional;
#Component
#Transactional
public interface TestDao {
#Transactional(propagation = Propagation.REQUIRED)
public void first();
}
I have read that this is very bad style. Using this answer at stackoverflow , here is explain and examples why is this bad - we must not add this annotation in DAO and in controller too. We must add it in service layer.
But I don't understand what is the service layer? Or where is it? I do not have anything like this.
where should I write #Transactional annotation?
Best regards,
According to the cited post, you should design your classes somehow like this (rather pseudocode):
controller (responsible for handling clients' requests/responses)
#Controller
#RequestMapping("/data")
public class TestREST {
#Autowired
private TestService service;
public void storePayment(PaymentDTO dto) {
service.storePayment(dto); //request from a client
}
public PaymentDTO getPayment(int paymentId) {
return service.getPayment(paymentId); //response to a client
}
}
service layer (also called business layer, responsible for business logic - knows what to do with incoming messages, but does not know where they come from).
public class TestServiceImpl {
#Autowired
private TestDao dao;
#Transactional(propagation=Propagation.REQUIRED) //force transaction
public void storePayment(PaymentDTO paymentDto) {
// transform dto -> entity
dao.storePayment(paymentEntity); //read-write hence transaction is on
}
#Transactional(propagation=Propagation.NOT_SUPPORTED) //avoid transaction
public Payment getPayment(int paymentId) {
return dao.findPayment(paymentId); //read-only hence no transaction
}
}
data access layer (also called persistence layer, responsible for accessing database - knows how to use entity model / ORM, does not know anything about the upper service layer)
public class TestDAOImpl {
#PersistenceContext
private EntityManager em;
public void storePayment(PaymentEntity paymentEntity) {
em.persist(paymentEntity);
}
public PaymentEntity getPayment(int paymentId) {
return em.find(PaymentEntity.class, paymentId);
}
}
By this approach you get separation of concerns mentioned in the post. From the other hand such an approach (business layer vs data access layer) got a little dose of criticism from Adam Bien's on his blog ("JPA/EJB3 killed the DAO"). As you can see there is no a single solution for the problem, but I encourage to read some other opinions and apply the solution you find the most suitable for your needs.
When you call two Dao methods first & second from controller, 2 transactions will be done, one with starts before first method and ends after it's execution and the second one starts before second method starts and ends after it's execution. Whereas you create an additional class in between controller and dao (usually this is called service layer) and annotate it with #Transactional and call multiple Dao methods in it, a transaction is started at the start of service method and all the dao calls will be executed and transaction will be closed, which is what you require. And inject the Service into Controller.
Controller -> Service -> Dao
#Controller
#RequestMapping("/data")
public class PaymentTransaction {
#Autowired
private TestService service;
#RequestMapping(value = "/test", method = RequestMethod.POST)
#ResponseBody()
public String test(HttpServletRequest request) {
...
}
}
#Service
#Transactional
public class TestService {
#Autowired
private TestDao dao;
#Transactional
public void serviceCall(){
dao.first();
dao.second();
}
}
So I have something like the following:
public interface MyService {
#PreAuthorize("hasPermission(T(Name).OBJ, T(Action).GET)")
MyObj getObj(String id);
}
#Service
public class MyServiceImpl implements MyService {
#Override
#Transactional
public MyObj getObj(String id){
return dao.get(id);
}
}
#Controller
public class MyController {
#Resource(name="myServiceImpl")
private MyService service;
public MyObj getObj(String id){
return service.getObj(id);
}
}
When the method getObj(id) is called, everything is wrapped in a transaction first, then authorization is checked. Is is possible to keep this configuration and first get Spring to check for authorization, then create the transaction if the user is authorized?
I've spent a good deal searching for an answer and could not find anything.
You can use order attribute when configuring #Transactional:
<tx:annotation-driven order="100"/>
Experiment with lower values to move transaction aspect after the authorization one. Looks like <security:global-method-security/> also has this setting. The security aspect needs to have a higher value (lower priority) to be executed first.
See also
Table 10.2. settings
7.2.4.7 Advice ordering