使用不是主键字段映射的JPA?

我很难让这个工作起来,我想知道我所做的只是没有意义吗?

public class Application {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name="id")
    private long id;
    ....
}

@MappedSuperclass
public abstract class Sample {
    @Id @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;

    @OneToOne (cascade=CascadeType.ALL)
    protected Application application;
    ....
}

// TestSample contains a list that is mapped not by the primary key of the Sample
public class TestSample extends Sample {
    @OneToMany(mappedBy="application", cascade=CascadeType.ALL, fetch=FetchType.LAZY)
    private List<Part> parts = new ArrayList<Part>();
    ....
}

public class Part {
    @Id @GeneratedValue(strategy = GenerationType.AUTO)
    private long id = 0;

    @ManyToOne (cascade=CascadeType.ALL, fetch=FetchType.LAZY)
    Application application;
}

parts 我得到一张空名单。

如果我通过更改这些类来破坏数据库结构,则可以使其正常工作:

// TestSample contains a list that is mapped not by the primary key of the Sample
public class TestSample extends Sample {
    @OneToMany(mappedBy="testSample", cascade=CascadeType.ALL, fetch=FetchType.LAZY)
    private List<Part> parts = new ArrayList<Part>();
    ....
}

public class Part {
    @Id @GeneratedValue(strategy = GenerationType.AUTO)
    private long id = 0;

    @ManyToOne (cascade=CascadeType.ALL, fetch=FetchType.LAZY)
    TestSample testSample;
}

application
  id : number
  ....

test_sample
  id : number
  application_id : number
  ...

part
  id : number
  application_id : number

如果我将其更改为不太理想的工作方式,则最后一个表会有所不同:

part
  id : number
  test_sample_id : number

因为id在所有情况下都是自动生成的,所以没有共享的主键。实际上,我要做的是使用mappedby,其中mappedby引用的字段不是名为“TestSample”的表/类的主键。我不确定这在JPA中是否有意义。