在Spring Data JPA中处理实体继承的最佳方法 [英] Best way of handling entities inheritance in Spring Data JPA

问题描述

我有三个 JPA实体类 A ， B 和 C 具有以下层次结构：

I've three JPA entity classes A, B and C with the following hierarchy:

    A
    |
+---+---+
|       |
C       B

即：

@Entity
@Inheritance
public abstract class A { /* ... */ }

@Entity
public class B extends A { /* ... */ }

@Entity
public class C extends A { /* ... */ }

使用 Spring Data JPA ，编写存储库类的最佳方法是什么这样的实体？

Using Spring Data JPA, what is the best way to write repositories classes for such entities?

我知道我可以写这些：

public interface ARespository extends CrudRepository<A, Long> { }

public interface BRespository extends CrudRepository<B, Long> { }

public interface CRespository extends CrudRepository<C, Long> { }

但如果在班级 A 有一个字段 name ，我在 ARepository 中添加了这个方法：

but if in the class A there is a field name and I add this method in the ARepository:

public A findByName(String name);

我还要在其他两个存储库中编写这样的方法，这有点烦人。有没有更好的方法来处理这种情况？

I've to write such method also in the other two repositories, and this is a bit annoying.. Is there a better way to handle such situation?

我想要的另一点是 ARespository 应该是一个只读存储库（即扩展存储库类），而其他两个存储库应该公开所有CRUD操作。

Another point I would like to have is that ARespository should be a read-only repository (i.e. extend the Repository class) while the other two repositories should expose all the CRUD operations.

让我知道可能的解决方案。

Let me know possible solutions.

推荐答案

我使用了这篇文章。

我们的想法是创建一个泛型存储库类，如下所示：

The idea is to create a generic repository class like the following:

@NoRepositoryBean
public interface ABaseRepository<T extends A> 
extends CrudRepository<T, Long> {
  // All methods in this repository will be available in the ARepository,
  // in the BRepository and in the CRepository.
  // ...
}

然后我可以写三个存储库以这种方式：

then I can write the three repositories in this way:

@Transactional
public interface ARepository extends ABaseRepository<A> { /* ... */ }

@Transactional
public interface BRepository extends ABaseRepository<B> { /* ... */ }

@Transactional
public interface CRepository extends ABaseRepository<C> { /* ... */ }

此外，要获取<$的只读存储库c $ c> ARepository 我可以将 ABaseRepository 定义为只读：

Moreover, to obtain a read-only repository for ARepository I can define the ABaseRepository as read-only:

@NoRepositoryBean
public interface ABaseRepository<T> 
extends Repository<T, Long> {
  T findOne(Long id);
  Iterable<T> findAll();
  Iterable<T> findAll(Sort sort);
  Page<T> findAll(Pageable pageable);
}

和 BRepository 扩展Spring Data JPA的 CrudRepository 以实现读/写存储库：

and from BRepository extend also the Spring Data JPA's CrudRepository to achieve a read/write repository:

@Transactional
public interface BRepository 
extends ABaseRepository<B>, CrudRepository<B, Long> 
{ /* ... */ }

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