java如何更新实体，而不是使用Hibernate将其插入数据库？

Question

例如，我有一个Job实体和一个worker实体。 当我添加新作业时，我希望为其分配工人，而不是将其用户添加到 再次创建数据库（并创建副本）我只想更新workers （当我使用worker list创建新工单时，将工单添加到工单中）

例如：

@Entity
@Table(name = "job")
@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
public class Job{

  @Id
  @Column(name = "id")
  private Long id;


  @OneToMany(mappedBy = "job", fetch = FetchType.EAGER)
  private Set<Worker> workers;
}

---

@Entity
@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@Table(name = "workers")
public class User extends DataAudit {

  @Id
  private Long id;


  @ManyToOne(fetch = FetchType.LAZY)
  @JoinColumn(name = "job_id", referencedColumnName = "id")
  private Job job;

}

---

Worker worker1 = workerService.getWorkerById(1);
Job job = new Job(1,worker1)
jobRepo.save(job)

Answer 1

实体应使用双向OneToMany关联@JoinTable：

@Entity
@Table(name = "job")
@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
public class Job{

  @Id
  @Column(name = "id")
  private Long id;


  @OneToMany(fetch=FetchType.LAZY)
  @JoinTable(name="job_workers", 
    joinColumns={@JoinColumn(name="job_id")},
    inverseJoinColumns={@JoinColumn(name="worker_id")}
  )
  @Cascade(org.hibernate.annotations.CascadeType.ALL)
  private Set<Worker> workers;
}

////////////////////////////////////////////////////////

@Entity
@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@Table(name = "workers")
public class User extends DataAudit {

  @Id
  private Long id;


  @ManyToOne
  @JoinTable(name="job_workers", 
    joinColumns={@JoinColumn(name="worker_id", insertable=false,updatable=false)},
    inverseJoinColumns={@JoinColumn(name="job_id", insertable=false,updatable=false)})
  private Job job;

}