How to add custom method to Spring Data JPA
JavaSpring DataSpring Data-JpaJava Problem Overview
I am looking into Spring Data JPA. Consider the below example where I will get all the crud and finder functionality working by default and if I want to customize a finder then that can be also done easily in the interface itself.
@Transactional(readOnly = true)
public interface AccountRepository extends JpaRepository<Account, Long> {
@Query("<JPQ statement here>")
List<Account> findByCustomer(Customer customer);
}
I would like to know how can I add a complete custom method with its implementation for the above AccountRepository? Since its an Interface I cannot implement the method there.
Java Solutions
Solution 1 - Java
You need to create a separate interface for your custom methods:
public interface AccountRepository
extends JpaRepository<Account, Long>, AccountRepositoryCustom { ... }
public interface AccountRepositoryCustom {
public void customMethod();
}
and provide an implementation class for that interface:
public class AccountRepositoryImpl implements AccountRepositoryCustom {
@Autowired
@Lazy
AccountRepository accountRepository; /* Optional - if you need it */
public void customMethod() { ... }
}
See also:
-
Note that the naming scheme has changed between versions. See https://stackoverflow.com/a/52624752/66686 for details.
Solution 2 - Java
In addition to axtavt's answer, don't forget you can inject Entity Manager in your custom implementation if you need it to build your queries:
public class AccountRepositoryImpl implements AccountRepositoryCustom {
@PersistenceContext
private EntityManager em;
public void customMethod() {
...
em.createQuery(yourCriteria);
...
}
}
Solution 3 - Java
There's a slightly modified solution that does not require additional interfaces.
As specificed in the documented functionality, the Impl
suffix allows us to have such clean solution:
- Define in you regular
@Repository
interface, sayMyEntityRepository
the custom methods (in addition to your Spring Data methods) - Create a class
MyEntityRepositoryImpl
(theImpl
suffix is the magic) anywhere (doesn't even need to be in the same package) that implements the custom methods only and annotate such class with@Component
** (@Repository
will not work).- This class can even inject
MyEntityRepository
via@Autowired
for use in the custom methods.
- This class can even inject
Example:
Entity class (for completeness):
package myapp.domain.myentity;
@Entity
public class MyEntity {
@Id private Long id;
@Column private String comment;
}
Repository interface:
package myapp.domain.myentity;
@Repository
public interface MyEntityRepository extends JpaRepository<MyEntity, Long> {
// EXAMPLE SPRING DATA METHOD
List<MyEntity> findByCommentEndsWith(String x);
List<MyEntity> doSomeHql(Long id); // custom method, code at *Impl class below
List<MyEntity> useTheRepo(Long id); // custom method, code at *Impl class below
}
Custom methods implementation bean:
package myapp.infrastructure.myentity;
@Component // Must be @Component !!
public class MyEntityRepositoryImpl { // must have the exact repo name + Impl !!
@PersistenceContext
private EntityManager entityManager;
@Autowired
private MyEntityRepository myEntityRepository;
@SuppressWarnings("unused")
public List<MyEntity> doSomeHql(Long id) {
String hql = "SELECT eFROM MyEntity e WHERE e.id = :id";
TypedQuery<MyEntity> query = entityManager.createQuery(hql, MyEntity.class);
query.setParameter("id", id);
return query.getResultList();
}
@SuppressWarnings("unused")
public List<MyEntity> useTheRepo(Long id) {
List<MyEntity> es = doSomeHql(id);
es.addAll(myEntityRepository.findByCommentEndsWith("DO"));
es.add(myEntityRepository.findById(2L).get());
return es;
}
}
Usage:
// You just autowire the the MyEntityRepository as usual
// (the Impl class is just impl detail, the clients don't even know about it)
@Service
public class SomeService {
@Autowired
private MyEntityRepository myEntityRepository;
public void someMethod(String x, long y) {
// call any method as usual
myEntityRepository.findByCommentEndsWith(x);
myEntityRepository.doSomeHql(y);
}
}
And that's all, no need for any interfaces other than the Spring Data repo one you already have.
The only possible drawbacks I identified are:
-
The custom methods in the
Impl
class are marked as unused by the compiler, thus the@SuppressWarnings("unused")
suggestion. -
You have a limit of one
Impl
class. (Whereas in the regular fragment interfaces implementation the docs suggest you could have many.) -
If you place the
Impl
class at a different package and your test uses only@DataJpaTest
, you have to add@ComponentScan("package.of.the.impl.clazz")
to your test, so Spring loads it.
Solution 4 - Java
The accepted answer works, but has three problems:
- It uses an undocumented Spring Data feature when naming the custom implementation as
AccountRepositoryImpl
. The documentation clearly states that it has to be calledAccountRepositoryCustomImpl
, the custom interface name plusImpl
- You cannot use constructor injection, only
@Autowired
, that are considered bad practice - You have a circular dependency inside of the custom implementation (that's why you cannot use constructor injection).
I found a way to make it perfect, though not without using another undocumented Spring Data feature:
public interface AccountRepository extends AccountRepositoryBasic,
AccountRepositoryCustom
{
}
public interface AccountRepositoryBasic extends JpaRepository<Account, Long>
{
// standard Spring Data methods, like findByLogin
}
public interface AccountRepositoryCustom
{
public void customMethod();
}
public class AccountRepositoryCustomImpl implements AccountRepositoryCustom
{
private final AccountRepositoryBasic accountRepositoryBasic;
// constructor-based injection
public AccountRepositoryCustomImpl(
AccountRepositoryBasic accountRepositoryBasic)
{
this.accountRepositoryBasic = accountRepositoryBasic;
}
public void customMethod()
{
// we can call all basic Spring Data methods using
// accountRepositoryBasic
}
}
Solution 5 - Java
This is limited in usage, but for simple custom methods you can use default interface methods like:
import demo.database.Customer;
import org.springframework.data.repository.CrudRepository;
public interface CustomerService extends CrudRepository<Customer, Long> {
default void addSomeCustomers() {
Customer[] customers = {
new Customer("Józef", "Nowak", "[email protected]", 679856885, "Rzeszów", "Podkarpackie", "35-061", "Zamknięta 12"),
new Customer("Adrian", "Mularczyk", "[email protected]", 867569344, "Krosno", "Podkarpackie", "32-442", "Hynka 3/16"),
new Customer("Kazimierz", "Dejna", "[email protected]", 996435876, "Jarosław", "Podkarpackie", "25-122", "Korotyńskiego 11"),
new Customer("Celina", "Dykiel", "[email protected]", 947845734, "Żywiec", "Śląskie", "54-333", "Polna 29")
};
for (Customer customer : customers) {
save(customer);
}
}
}
EDIT:
In this spring tutorial it is written:
> Spring Data JPA also allows you to define other query methods by > simply declaring their method signature.
So it is even possible to just declare method like:
Customer findByHobby(Hobby personHobby);
and if object Hobby
is a property of Customer then Spring will automatically define method for you.
Solution 6 - Java
Im using the following code in order to access generated find methods from my custom implementation. Getting the implementation through the bean factory prevents circular bean creation problems.
public class MyRepositoryImpl implements MyRepositoryExtensions, BeanFactoryAware {
private BrandRepository myRepository;
public MyBean findOne(int first, int second) {
return myRepository.findOne(new Id(first, second));
}
public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
myRepository = beanFactory.getBean(MyRepository.class);
}
}
Solution 7 - Java
Considering your code snippet, please note that you can only pass Native objects to the findBy### method, lets say you want to load a list of accounts that belongs certain costumers, one solution is to do this,
@Query("Select a from Account a where a."#nameoffield"=?1")
List<Account> findByCustomer(String "#nameoffield");
Make sue the name of the table to be queried is thesame as the Entity class. For further implementations please take a look at this
Solution 8 - Java
If you want to be able to do more sophisticated operations you might need access to Spring Data's internals, in which case the following works (as my interim solution to DATAJPA-422):
public class AccountRepositoryImpl implements AccountRepositoryCustom {
@PersistenceContext
private EntityManager entityManager;
private JpaEntityInformation<Account, ?> entityInformation;
@PostConstruct
public void postConstruct() {
this.entityInformation = JpaEntityInformationSupport.getMetadata(Account.class, entityManager);
}
@Override
@Transactional
public Account saveWithReferenceToOrganisation(Account entity, long referralId) {
entity.setOrganisation(entityManager.getReference(Organisation.class, organisationId));
return save(entity);
}
private Account save(Account entity) {
// save in same way as SimpleJpaRepository
if (entityInformation.isNew(entity)) {
entityManager.persist(entity);
return entity;
} else {
return entityManager.merge(entity);
}
}
}
Solution 9 - Java
There is another issue to be considered here. Some people expect that adding custom method to your repository will automatically expose them as REST services under '/search' link. This is unfortunately not the case. Spring doesn't support that currently.
This is 'by design' feature, spring data rest explicitly checks if method is a custom method and doesn't expose it as a REST search link:
private boolean isQueryMethodCandidate(Method method) {
return isQueryAnnotationPresentOn(method) || !isCustomMethod(method) && !isBaseClassMethod(method);
}
This is a qoute of Oliver Gierke:
> This is by design. Custom repository methods are no query methods as > they can effectively implement any behavior. Thus, it's currently > impossible for us to decide about the HTTP method to expose the method > under. POST would be the safest option but that's not in line with the > generic query methods (which receive GET).
For more details see this issue: https://jira.spring.io/browse/DATAREST-206
Solution 10 - Java
Adding custom behavior to all repositories :
To add custom behavior to all repositories, you first add an intermediate interface to declare the shared behavior.
public interface MyRepository <T, ID extends Serializable> extends JpaRepository<T, ID>
{
void sharedCustomMethod( ID id );
}
Now your individual repository interfaces will extend this intermediate interface instead of the Repository interface to include the functionality declared.
Next, create an implementation of the intermediate interface that extends the persistence technology-specific repository base class. This class will then act as a custom base class for the repository proxies.
public class MyRepositoryImpl <T, ID extends Serializable> extends SimpleJpaRepository<T, ID> implements MyRepository<T, ID>
{
private EntityManager entityManager;
// There are two constructors to choose from, either can be used.
public MyRepositoryImpl(Class<T> domainClass, EntityManager entityManager)
{
super( domainClass, entityManager );
// This is the recommended method for accessing inherited class dependencies.
this.entityManager = entityManager;
}
public void sharedCustomMethod( ID id )
{
// implementation goes here
}
}
Solution 11 - Java
I liked Danila's solution and started using it but nobody else on the team liked having to create 4 classes for each repository. Danila's solution is the only one here that let's you use the Spring Data methods in the Impl class. However, I found a way to do it with just a single class:
public interface UserRepository extends MongoAccess, PagingAndSortingRepository<User> {
List<User> getByUsername(String username);
default List<User> getByUsernameCustom(String username) {
// Can call Spring Data methods!
findAll();
// Can write your own!
MongoOperations operations = getMongoOperations();
return operations.find(new Query(Criteria.where("username").is(username)), User.class);
}
}
You just need some way of getting access to your db bean (in this example, MongoOperations). MongoAccess provides that access to all of your repositories by retrieving the bean directly:
public interface MongoAccess {
default MongoOperations getMongoOperations() {
return BeanAccessor.getSingleton(MongoOperations.class);
}
}
Where BeanAccessor is:
@Component
public class BeanAccessor implements ApplicationContextAware {
private static ApplicationContext applicationContext;
public static <T> T getSingleton(Class<T> clazz){
return applicationContext.getBean(clazz);
}
public static <T> T getSingleton(String beanName, Class<T> clazz){
return applicationContext.getBean(beanName, clazz);
}
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
BeanAccessor.applicationContext = applicationContext;
}
}
Unfortunately, you can't @Autowire in an interface. You could autowire the bean into a MongoAccessImpl and provide a method in the interface to access it, but Spring Data blows up. I don't think it expects to see an Impl associated even indirectly with PagingAndSortingRepository.
Solution 12 - Java
I faced with this using mongo and spring. So let's assume we use MongoRepository to provided base crud operations, and let's say we need to implement some custom criteria query operation using mongoTemplate. To achieve one interface to inject repository for crud and custom we need to specify:
Custom interface:
public interface UserCustomRepository {
List<User> findAllUsersBySomeCriteria(UserCriteriaRequest criteriaRequest);
}
UserRepository interface 'must' first extends UserCustomRepository and then MongoRepository
@Repository
public interface UserRepository extends UserCustomRepository, MongoRepository<User, ObjectId> {
}
UserRepositoryImpl must have the same name as what crud interface with *Impl suffix.
@Component
@NoArgsConstructor
@AllArgsConstructor(onConstructor = @__(@Autowired))
public class UserRepositoryImpl implements UserCustomRepository {
private MongoTemplate mongoTemplate;
@Override
public List<User> findAllUsersBySomeCriteria(UserCriteriaRequest criteriaRequest){
//some impl
}
}
Let's impl some service - here we inject only UserRepository interface and use methods from crud repository and custom class impl.
@Service
@NoArgsConstructor
@AllArgsConstructor(onConstructor = @__(@Autowired))
public class UserService {
private UserRepository userReposityry;
public List<User> getUserByCriteria(UserCriteriaRequest request) {
userRepository.findById(request.getUserId); // Crud repository method
userRepository.findAllUsersBySomeCriteria(request); // custom method.
}
}
Solution 13 - Java
I extends the SimpleJpaRepository:
public class ExtendedRepositoryImpl<T extends EntityBean> extends SimpleJpaRepository<T, Long>
implements ExtendedRepository<T> {
private final JpaEntityInformation<T, ?> entityInformation;
private final EntityManager em;
public ExtendedRepositoryImpl(final JpaEntityInformation<T, ?> entityInformation,
final EntityManager entityManager) {
super(entityInformation, entityManager);
this.entityInformation = entityInformation;
this.em = entityManager;
}
}
and adds this class to @EnableJpaRepositoryries repositoryBaseClass.
Solution 14 - Java
I use SimpleJpaRepository as the base class of repository implementation and add custom method in the interface,eg:
public interface UserRepository {
User FindOrInsert(int userId);
}
@Repository
public class UserRepositoryImpl extends SimpleJpaRepository implements UserRepository {
private RedisClient redisClient;
public UserRepositoryImpl(RedisClient redisClient, EntityManager em) {
super(User.class, em);
this.redisClient = redisClient;
}
@Override
public User FindOrInsert(int userId) {
User u = redisClient.getOrSet("test key.. User.class, () -> {
Optional<User> ou = this.findById(Integer.valueOf(userId));
return ou.get();
});
…………
return u;
}