How to add custom method to Spring Data JPA

Question

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 lt Account  Long gt        Query   lt JPQ statement here gt      List lt Account gt  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

User · Answer

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 called AccountRepositoryCustomImpl  the custom interface name plus Impl 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 lt Account  Long gt           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

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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   amp  amp   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

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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 lt Customer  Long gt          default void addSomeCustomers             Customer   customers                 new Customer  J  zef    Nowak    nowakJ o2 pl   679856885   Rzesz  w    Podkarpackie    35-061    Zamknieta 12                new Customer  Adrian    Mularczyk    adii333 wp pl   867569344   Krosno    Podkarpackie    32-442    Hynka 3 16                new Customer  Kazimierz    Dejna    sobieski22 weebly com   996435876   Jaroslaw    Podkarpackie    25-122    Korotynskiego 11                new Customer  Celina    Dykiel    celina dykiel39 yahoo org   947845734   Zywiec    Slaskie    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

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I extends the SimpleJpaRepository   public class ExtendedRepositoryImpl lt T extends EntityBean gt  extends SimpleJpaRepository lt T  Long gt      implements ExtendedRepository lt T gt         private final JpaEntityInformation lt T    gt  entityInformation       private final EntityManager em       public ExtendedRepositoryImpl final JpaEntityInformation lt T    gt  entityInformation                                                        final EntityManager entityManager           super entityInformation  entityManager          this entityInformation   entityInformation         this em   entityManager            and adds this class to  EnableJpaRepositoryries repositoryBaseClass

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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  say MyEntityRepository the custom methods  in addition to your Spring Data methods  Create a class MyEntityRepositoryImpl  the Impl 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      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 lt MyEntity  Long gt            EXAMPLE SPRING DATA METHOD     List lt MyEntity gt  findByCommentEndsWith String x        List lt MyEntity gt  doSomeHql Long id        custom method  code at  Impl class below      List lt MyEntity gt  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  quot unused quot       public List lt MyEntity gt  doSomeHql Long id            String hql    quot SELECT eFROM MyEntity e WHERE e id    id quot           TypedQuery lt MyEntity gt  query   entityManager createQuery hql  MyEntity class           query setParameter  quot id quot   id           return query getResultList                SuppressWarnings  quot unused quot       public List lt MyEntity gt  useTheRepo Long id            List lt MyEntity gt  es   doSomeHql id           es addAll myEntityRepository findByCommentEndsWith  quot DO quot             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  quot unused quot   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  quot package of the impl clazz quot   to your test  so Spring loads it

User · Answer

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  lt T  ID extends Serializable gt  extends JpaRepository lt T  ID gt             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  lt T  ID extends Serializable gt  extends SimpleJpaRepository lt T  ID gt  implements MyRepository lt T  ID gt             private EntityManager entityManager                 There are two constructors to choose from  either can be used      public MyRepositoryImpl Class lt T gt  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          Spring Data Repositories Part I  Reference

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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  quot Select a from Account a where a  quot  nameoffield quot   1 quot   List lt Account gt  findByCustomer String  quot  nameoffield quot     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

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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

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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 lt User gt         List lt User gt  getByUsername String username         default List lt User gt  getByUsernameCustom String username               Can call Spring Data methods          findAll                Can write your own          MongoOperations operations   getMongoOperations            return operations find new Query Criteria where  quot username quot   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  lt T gt  T getSingleton Class lt T gt  clazz           return applicationContext getBean clazz              public static  lt T gt  T getSingleton String beanName  Class lt T gt  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

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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

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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  quot test key   User class     - gt            Optional lt User gt  ou   this findById Integer valueOf userId            return ou get                                 return u

User · Answer

You need to create a separate interface for your custom methods   public interface AccountRepository      extends JpaRepository lt Account  Long gt   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    4 6 Custom Implementations for Spring Data Repositories Note that the naming scheme has changed between versions  See https   stackoverflow com a 52624752 66686 for details

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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 lt Account    gt  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

[java] How to add custom method to Spring Data JPA

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