hibernate - JPA，Hibernate我可以组合哪个主键是国外凯@OneToMany的复合主键吗？

我想在我的实体中包含由2列(属性)组成的复合主键，并将其中之一同时作为外键。

我写这样的东西，但不知道它是否有效，因为在IntelliJ数据源中将外键标记为生成值

@Entity
@Table(name = "service_point")
@Access(AccessType.PROPERTY)
@IdClass(ServicePointId.class)
public class ServicePoint {

    private Long providerId;
    private Integer servicePointNumber;

    private Provider provider;

    @Id
    @Basic(optional = false)
    @Column(name = "provider_id", nullable = false, insertable = false,
            updatable = false, columnDefinition = "BIGINT UNSIGNED")
    public Long getProviderId() {
        return providerId;
    }

    public void setProviderId(Long providerId) {
        this.providerId = providerId;
    }

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "service_point_no", nullable = false, columnDefinition = "BIGINT UNSIGNED")
    public Integer getServicePointNumber() {
        return servicePointNumber;
    }

    public void setServicePointNumber(Integer servicePointNumber) {
        this.servicePointNumber = servicePointNumber;
    }

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "provider_id")
    public Provider getProvider() {
        return provider;
    }

    public void setProvider(Provider provider) {
        this.provider = provider;
    }
}

更新:

我已经测试了Brian Vosburgh，它可以工作:

transaction.begin();

em.persist(provider);

ServicePoint servicePoint = new ServicePoint(provider, 1);

em.persist(servicePoint);

transaction.commit();

ServicePoint servicePoint2 = em.find(ServicePoint.class,
        new ServicePointId(provider.getUserId(), servicePoint.getServicePointNumber()));

assertTrue("Service point provider id and Provider provider id should be the same.",
        servicePoint2.getProvider().getUserId() == provider.getUserId());
assertNotNull("Service point number can not be null", servicePoint2.getServicePointNumber());
assertEquals(servicePoint2.getProvider(), provider);

transaction.begin();
em.remove(servicePoint);
em.remove(provider);
transaction.commit();

更新2-下一个关系复合PK中的新问题(3列)，其中2个是复合FK oj​​it_rstrong
我一直在尝试类似于以下解决方案，但无法通过
如何编写ServicePointPhotoId @IdClass

最佳答案

摆脱providerId字段及其对应的getter和setter。在@Id中添加getProvider()批注。像这样定义IdClass:

public class ServicePointId {
    private Long provider;
    private Integer servicePointNumber;
    public Integer getProvider() {
        return provider;
    }
    public void setProvider(Integer provider) {
        this.provider = provider;
    }
    public Integer getServicePointNumber() {
        return servicePointNumber;
    }
    public void setServicePointNumber(Integer servicePointNumber) {
        this.servicePointNumber = servicePointNumber;
    }
}

请注意，IdClass中的属性名称与Entity中的属性名称(即provider)匹配，但是属性的类型不同。在IdClass中，属性类型必须与Id的Provider属性的类型匹配。

在JPA 2.1规范的2.4.1节中对此进行了讨论。

UPDATE 2的建议

public class ServicePointPhotoId {
    public ServicePointId servicePoint;
    public Long photoId;
}

@Entity
@IdClass(ServicePointPhotoId.class)
@Table(name="service_point_photo")
public class ServicePointPhoto {
    @Id
    @ManyToOne
    @JoinColumns({
        @JoinColumn(name="provider_id", referencedColumnName="provider_id"),
        @JoinColumn(name="service_point_no", referencedColumnName="service_point_no")
    })
    private ServicePoint servicePoint;

    @Id
    @Column(name="photo_id")
    private Long photoId;
}

请注意，属性名称必须匹配(即servicePoint)；但IdClass属性的类型必须与引用的Entity的IdClass(即ServicePointId)匹配。

我使用了字段注释，但是您可以将其转换为属性注释。

再次:JPA 2.1规范在2.4.1.3节中仅提供了这种关系的示例。