正确映射(JPA)组合键

Question

例如我有实体

@Entity
public class A{
@Id
Long Id;
...
}
@Entity
public class B{
@Id
Long Id;
...
}
@Entity
@IdClass(ABId.class).
public class AB{
@Id
@ManyToOne
private A a;
@Id
@ManyToOne
private B b;
private boolean state;
}
Class for composite primary key:
public ABId implements Serializable{
Long a;
Long b;
.........
}

，我想从类A中得到这样的东西select * from AB AB where AB .a_id=1;(id from A object)

我在类A中做了这样的映射

@OneToMany(fetch = FetchType.EAGER)
@JoinColumns({
@JoinColumn(name="A_id", referencedColumnName="id"),
@JoinColumn(name="B_id", referencedColumnName="id")
})
List<AB> listAB;

但是它什么也不做，我总是得到空列表。

Answer 1

已解决，

I did mapping

@OneToMany(fetch = FetchType.EAGER)
@JoinColumns({
@JoinColumn(name="A_id", referencedColumnName="id")
})
List<AB> listAB;

并正常工作