Spring JPA-带有两个主键的实体

Question

@Entity
public class Label {

    @Id
    @GeneratedValue
    private Long id;

    @ManyToOne
    @JoinColumn(name = "text_id")
    private Text text;

}

@Entity
public class Text {

    @Id
    @GeneratedValue
    private Long id;

    @Column(name = "text", columnDefinition = "TEXT")
    private String text;

    @OneToMany(mappedBy = "text")
    private List<Label> labels;

    @ManyToOne
    @JoinColumn(name = "language_id")
    private Language language;

}

@Entity
public class Language {

    @Id
    @GeneratedValue
    private Long id;

    @Column(name = "code")
    private String code;

    @OneToMany(mappedBy = "language")
    private List<Text> texts;

}

text_id     language_id     text
------------------------------------
1           1               Example
1           2               Beispiel

Answer 1

您可以在这里找到两种解决方案：如何在JPA中创建和处理复合主键

• 第一个基于@embeddable类。
• 第二个基于@idclass类。

@IDClass解决方案摘要：

public class LabelRepositoryKey implements Serializable {
  private Long textId;
  private Long languageId;
}

@Entity @IdClass(LabelRepositoryKey.class)
public class LabelRepository {
  @Id
  private Long textId;
  @Id
  private Long languageId;
  @Column(name = "text")
  private String text;
}