Question

我有两个实体Resource（表资源）和VideoInfo（表video_info），从VideoInfo到Resource存在一对一的单向关系。以下代码保存一对一关系，但保存的列resource.id不等于video_info.resourceId。注释有什么问题吗？我知道我可以手动设置video_info.resourceId等于Resource.id，是否存在任何自动方式？

public static void main(String[] args) throws IOException {
    Resource r=new Resource();
    r.setName("test");
    r.setPath("foo");
    r.setType("video");
    VideoInfo videoInfo=new VideoInfo();
    videoInfo.setResource(r);
    Session session=Database.getSessionFactory().openSession();
    Transaction transaction=session.beginTransaction();
    try {
        session.save(videoInfo);
        transaction.commit();
    }catch (Exception e){
        transaction.rollback();
        return;
    }
    System.out.println(r.getId());
    System.out.println(videoInfo.getResourceId());
}

输出：

19
0

VideoInfo实体：

@Entity
@Table(name = "video_info")
public class VideoInfo {
    @Id
    private int resourceId;
    @Column(name = "type")
    private String type;
    @Column(name = "time")
    private Integer time;
    @Column(name = "actors")
    private String actors;
    @OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @JoinColumn(name = "resourceId")
    private Resource resource;

    //getters and setters

}

资源实体：

@Entity
@Table(name = "resource")
public class Resource {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;
    @Column(name = "name")
    private String name;
    @Column(name = "path")
    private String path;
    @Column(name = "type")
    private String type;

    //getters and setters
}

Answer 1

您是否尝试过@PrimaryKeyJoinColumn注释？

像这样：

@OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
@PrimaryKeyJoinColumn
private Resource resource;

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Answer 2

让我回答我的问题：正如此链接@OneToOne With Shared Primary Key, Revisited所说，我应该使用@MapsId注释。

@Entity
@Table(name = "video_info")
public class VideoInfo {
    @Id
    private int resourceId;
    @Column(name = "type")
    private String type;
    @Column(name = "time")
    private Integer time;
    @Column(name = "actors")
    private String actors;
    @OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @JoinColumn(name = "resourceId")
    @MapsId
    private Resource resource;

    //getters and setters
}

hibernate一对一映射，如何使两个实体具有相同的主键

2 个答案: