JPA-2@manytomany两个实体之间的关系（其中一个有额外的实体）

Question

我在这里粘贴类：

链类：

@Entity
@Table(name = "chain")
public class Chain {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;

    @NotBlank(message = "Chain name is mandatory")
    private String name;

    @Column(name = "PLANT_NAME")
    private String plantName;

    private String description;

    private String status;

    private Boolean hasPlant;

    @CreationTimestamp
    @Column(name = "creation_time")
    private LocalDateTime creationTime;

    @OneToMany(mappedBy = "camera_item")
    private List<CameraItem> cameraItems = new ArrayList<>();

    @OneToMany(mappedBy = "chain")
    Set<ConnectionPoint> connectionPoints;

相机项目类别：

@Entity
@Table(name = "camera_item")
public class CameraItem {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;

    @ManyToOne
    @JoinColumn
    private Camera camera;

    private String name;

    private Integer positionInChain;

    @ManyToMany(mappedBy = "cameraItems", fetch = FetchType.LAZY)
    private List<Chain> parentChainIds;
    

    @OneToMany(mappedBy = "cameraItem")
    Set<ConnectionPoint> connectionPoints;

@Entity
@Table(name = "connection_point")
public class ConnectionPoint {

    @Id
    private Long id;

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

    @ManyToOne
    @JoinColumn(name = "chain")
    private Chain chain;

    @ManyToOne
    @JoinColumn(name = "camera_item")
    private CameraItem cameraItem;

Answer 1

我认为ConnectionPoint中没有问题。我认为问题是：

在链类中，

@OneToMany(mappedBy = "camera_item")  // One-to-Many defined here
private List<CameraItem> cameraItems = new ArrayList<>();

在CameraItem类中，相应的属性定义如下：

@ManyToMany(mappedBy = "cameraItems", fetch = FetchType.LAZY) // Many-To-Many
private List<Chain> parentChainIds;