java - 在 Spring Data JPA 中按类型查询

Question

我有抽象类:

@Entity
@Inheritance(strategy = InheritanceType.JOINED)
public abstract class A {
  ...
}

和一些扩展类，例如:

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

我还有第三个实体:

@Entity
public class C  {

  @OneToOne(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
  private A objectA;
  ...
}

问题是，我如何在 C 实体存储库中构造 Spring Data JPA 查找器以仅查询扩展 A 所需类型的对象？

Answer 1

您可以使用您已定义“类型”的鉴别器值的名称

@Entity
@Inheritance(strategy = InheritanceType.JOINED)
@DiscriminatorColumn(name = "type", discriminatorType = DiscriminatorType.STRING)
@Table(name = "abc")
public abstract class Abc {
....

-------------------------------------------

@Query("select a from Abc a where type = ?1")
List<Abc> findByType(String typeValue);