如何在 JPA/JAVA/Hibernate 中的两列中插入自动生成的 ID

Question

我在 DAO 类的 JPA java 中使用自动生成器生成 id。 由于愚蠢的数据库体系结构，我需要生成主键并将相同的 id 插入同一个表中的两列

@Id
@GeneratedValue(generator = DataConstants.ABC)
@Column(name = "SYS_ID")
private Long Sysid;

@Column(name = "SYS_NUM")
private Long sysNum;

现在我有上面的 DAO 类，它工作正常，并在 SYS_ID 列中插入自动生成的主键。

解决此问题的一种方法是插入数据并获取 sysid，然后对其运行更新，这对我来说似乎不可行。

任何帮助，将不胜感激

Answer 1

我最近遇到了类似的问题，并最终提出了以下解决方案：我使用 hibernate、panache、lombok 来描述我的实体：

大师.java

@Entity
@AllArgsConstructor
@NoArgsConstructor
@RegisterForReflection
@Table(name = "MASTER")
@FieldDefaults(level = AccessLevel.PUBLIC)
public class Master extends PanacheEntityBase {
    @Id
    @Column(name = "MASTERID", nullable = false)
    Long masterId;

    @Column(name = "DETAILID", nullable = false)
    Long detailId;

    @OneToMany(fetch = FetchType.EAGER, mappedBy = "master", cascade = {CascadeType.MERGE, CascadeType.PERSIST})
    Set<Detail> details = new HashSet<>(0);

    @Column(name = "DATECREATED", nullable = false)
    Date dateCreated;

    public static Master createMasterWithLoadId() {
        Query nativeQuery = Panache.getEntityManager().createNativeQuery("select MASTER_SEQ.nextval from dual");
        Master master = new Master();
        master.masterId = id;
        master.detailId = id;
        return master;
    }

     @PrePersist
     public void prePersist() {
        if (dateCreated == null) {
           dateCreated = clearTime(Calendar.getInstance()).getTime();
        }
     }

     private Calendar clearTime(Calendar cal) {
         cal.set(Calendar.HOUR_OF_DAY, 0);
         cal.set(Calendar.MINUTE, 0);
         cal.set(Calendar.SECOND, 0);
         cal.set(Calendar.MILLISECOND, 0);
         return cal;
     }
}

细节.java

@Entity
@NoArgsConstructor
@AllArgsConstructor
@RegisterForReflection
@IdClass(BatchContent.ContentId.class)
@Table(name = "DETAIL")
@FieldDefaults(level = AccessLevel.PUBLIC)
public class Detail extends PanacheEntityBase {
    @Id
    @ManyToOne(fetch = FetchType.EAGER, cascade = {CascadeType.MERGE, CascadeType.PERSIST})
    @JoinColumn(name = "detailId", nullable = false)
    Master master;

    @Id
    @Column(name = "one")
    Long one;

    @Id
    @Column(name = "two")
    Long two;

    @Getter
    @Setter
    @EqualsAndHashCode
    @NoArgsConstructor
    @AllArgsConstructor
    @RegisterForReflection
    @FieldDefaults(level = AccessLevel.PRIVATE)
    static class DetailId implements Serializable {

        Master master;

        Long one;

        Long two;

    }
}

采用：

Master master = Master.createMasterWithLoadId();
for (RequestDetail rDet : rDetails) {
    master.details.add(new Detail(master, rDet.getOne(), rDet.getTwo()));
}
master.persist();