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 t

Answer 1

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
{
    // 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
    }
}