JPA，Hibernate：子类的字段为空，@MappedSuperclass 和 InheritanceType.JOINED 策略

Question

我正在尝试保留 Person 实体，但我不断收到此空约束违规错误：

org.postgresql.util.PSQLException: ERROR: null value in column "created_by_party_id" violates not-null constraint
  Detail: Failing row contains (5023, John, null, Smith, null, 1, null, null, 2020-11-11 07:33:31.590766-05, null, null, null).

我尝试过的：

• 有和没有鉴别器注释
• 设置@PrePersist中的值
• 使用默认值在基类中初始化createdById
• 使 Party 类可实例化（不是抽象的），并直接将其持久化 - 可行，但这不是我需要的

由于某种原因，在生成 SQL 并将其传递给 PostgreSQL 时，createdById 为空。 （我已经在调试模式下验证了在 person 实体上设置了该字段，当它被传递到 DAO 保存调用时。）

我正在使用 Spring boot、Hibernate 和 PostgreSQL 来映射我的表和类，如下所示：

@MappedSuperclass
@EntityListeners( value = { EntityAuditListener.class } )
public abstract class BaseJPA {

    @Column(name = "created_by_party_id", nullable = false)
    private Long createdById = 1l;

    /* Getters and Setters ... */
}

public class EntityAuditListener {
    @PrePersist
    public void prePersist(BaseJPA jpa) {
        jpa.setCreatedById( 1l );
    }
}

Party 类虽然是抽象的，但映射到一个 PARTY 表：

@Entity(name = "Party")
@Table(name = "PARTY")
@Inheritance(strategy = InheritanceType.JOINED)
@DiscriminatorColumn(name = "PARTY_TYPE_CODE", discriminatorType = DiscriminatorType.INTEGER)
public abstract class Party extends BaseJPA implements Serializable {

    private static final long serialVersionUID = 5434024967600745049L;

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "PARTY_ID_SEQ")
    @SequenceGenerator(name = "PARTY_ID_SEQ", sequenceName = "PARTY_ID_SEQ", allocationSize = 1)
    @Column(name = "PARTY_ID")
    protected Long partyId;

    @Column(name = "PARTY_TYPE_CODE", insertable = false, updatable = false)
    protected PartyType partyType;

    /* Getters & Setters ... */
}

PartyType 枚举使用 AttributeConverter 注册，@Converter(autoApply = true)

public enum PartyType {
    PERSON(1), UNIT(2), SYSTEM(3);

    private final int value;

    PartyType(int value) {
        this.value = value;
    }
    /* Getter */
}

@Entity(name = "Person")
@Table(name = "PERSON")
@DiscriminatorValue( "1" )
@Inheritance(strategy = InheritanceType.JOINED)
public class Person extends Party implements Serializable {

    private static final long serialVersionUID = -5747077306637558893L;

    @Column(name = "FIRST_NAME")
    private String firstName;

    @Column(name = "LAST_NAME")
    private String lastName;

    /* More fields ...*/

    public Person() {
        this.partyType = PartyType.PERSON;
    }

    /* Getters & Setters */
}

Answer 1

您确定调用了实体侦听器方法吗？您确定没有其他方法可以将该值设置为 null 吗？

如果所有这些都没有帮助，请创建一个复制的test case 并将问题提交给Hibernate issue tracker。