休眠JPA连接两个表与另一个表

Question

我有两个表A和B

表A：

ID_A

名称

表B

ID_B

名称

我用它们的主键通过第三个表C表将它们连接在一起

表C

ID_C

ID_A

ID_B

我想知道在jpa映射中检索对象A内对象B列表的这种关系

谢谢，

Answer 1

类A具有C对象的列表。

class A{

@Id
private Long Id;

@Column(name = "name_a", length = 5)
private Strin name_a;

@OneToMany(cascade = CascadeType.ALL, mappedBy = "a", fetch = FetchType.LAZY)
private List<C> cList;
}
class B{

@Id
private Long Id;

@Column(name = "name_b", length = 5)
private String name_b;

@OneToMany(cascade = CascadeType.ALL, mappedBy = "b", fetch = FetchType.LAZY)
private List<C> cList;

}

这是联接表。类C具有A对象和B对象。

class C{

  @Id
  private Long id;

  @JoinColumn(name = "id_a", referencedColumnName = "id", nullable = false)
  @ManyToOne(optional = false, fetch = FetchType.LAZY)
  private A a;


  @JoinColumn(name = "id_b", referencedColumnName = "id", nullable = false)
  @ManyToOne(optional = false, fetch = FetchType.LAZY)
   private B b;


}

Answer 2

我在这里找到了一个很好的例子http://viralpatel.net/blogs/hibernate-many-to-many-annotation-mapping-tutorial/