Question

我正在使用Java + Spring + Hibernate

在测试以下代码时，我收到了错误消息：

javax.persistence.PersistenceException： org.hibernate.PropertyAccessException：无法获取字段值反射getter of com.XXX.XXX.entity.Policy.id

@Entity
@Table(name = "assignment")
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public class Assignment extends BaseEntity {

    @Id
    @Column(name = "id")
    @Type(type = "pg-uuid")
    @NotTracked
    private UUID id;

    @OneToOne(targetEntity = Policy.class)
    @JoinColumn(name = "policy_id", nullable = false, referencedColumnName = "policy_id")
    @OnDelete(action = OnDeleteAction.CASCADE)
    @TrackedEntity(isIdentityField = true)
    private UUID policyID;
}

@Entity
@Table(name = "policy")
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE, region = "policy")
@Inheritance(strategy = InheritanceType.JOINED)
public class Policy extends BaseEntity {

    @Id
    @Column(name = "policy_id")
    @Type(type = "pg-uuid")
    @NotTracked
    private UUID id;

    ...
    ...
    ..

}

将private UUID policyID;从UUID更改为Policy时，它的工作正常，有没有办法在某种程度上设置对Policy内部特定对象的引用作为ID，而不是保持整体Assignment对象中的策略对象？

Answer 1

可以只包含UUID，但它不再是hibernate托管的FK。我不建议您这样做，因为您希望Hibernate管理您的FK ..您只需将Assignment更改为：

@Entity
@Table(name = "assignment")
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public class Assignment extends BaseEntity {

    @Id
    @Column(name = "id")
    @Type(type = "pg-uuid")
    @NotTracked
    private UUID id;

    @Column(name="policy_id")
    private UUID policyID;
}

话虽如此，除非您手动将它们添加到数据库中，否则您将丢失所有Cascade选项和FK检查约束。

Answer 2

我认为没有理由使用UUID而不是对Policy-Object的引用。您可以注释您想要延迟加载对象，因此只有在您想要访问Policy-Object的另一个属性时才从数据库加载它：

@OneToOne（targetEntity = Policy.class，fetch = FetchType.LAZY）

@OneToOne使用@JoinColumn只保存UUID而不是整个对象

2 个答案: