J2-1 JPA Composite key

Summary

问题

一个id键，一个外键，我想把他俩弄成一个composite primary key。

虽然网上已经有很多教程，但是很多用起来会改变代码结果或是数据库结构。所以我使用了IdClass来解决问题，它仅仅引入增量代码来解决问题：

Steps:

Create an Id class.


@Data
@AllArgsConstructor
@NoArgsConstructor
public class MyIdClass implements Serializable {
    private Long id;
    private Long id2;
}

@IdClass(MyIdClass.class)
class dataObject {
}

Add two @Id annotations:


@IdClass(MyIdClass.class)
class dataObject {
  @Id
  Long id;

  @Id
	@Column(name = "FOREIGN_ID", nullable = false)
	Long id2;
	
	@ManyToOne(optional = false)
	@JoinColumn(
	        name = "FOREIGN_ID",
	        referencedColumnName = "REFERENCED_ID",
	        insertable = false,
	        updatable = false)
  private ReferencedObject referencedObject;
}