java - 如何在hibernate中不继承Id generatedValue(在子类中禁用@GenerateValue)

Question

我有一个 hibernate 实体父类(super class):

@MappedSuperclass
public abstract class Pojo_Entity_SuperClass 
{
   @Id
   @GeneratedValue(strategy=GenerationType.IDENTITY)
   @Column(name="ID", unique=true, nullable=false, precision=18, scale=0)
   protected long id;
   public Long getId() {return id;}

   //Other entity fields and methods
}

接下来我继承其他实体类，如下所示:

@Entity
@Table(name="USR")
public class Usr extends Pojo_Entity_SuperClass 
{
   //Columns, fileds and others
}

但在某些情况下，我想继承具有“id”字段的实体，而不使用 @GenerateValue 注释。问题是 - 如何在子类中禁用 id 的 @GenerateValue 注释？

Answer 1

您可以简单地将@Id从基类移动到子类，然后决定生成策略。

所以你可以:

@MappedSuperclass
public abstract class Pojo_Entity_SuperClass 
{   
    public abstract Long getId();

    public abstract void setId(Long id);

    //Other entity fields and methods
}

@Entity
@Table(name="USR")
public class Usr extends Pojo_Entity_SuperClass {
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name="ID", unique=true, nullable=false, precision=18, scale=0)
    protected long id;  
}

@Entity
@Table(name="ADMIN")
public class Admin extends Pojo_Entity_SuperClass {
    @Id
    @SequenceGenerator(name = "ID_GENERATOR", sequenceName = "admin_id_seq")
    @GeneratedValue(generator = "ID_GENERATOR")
    @Column(name="ID", unique=true, nullable=false, precision=18, scale=0)
    protected long id;  
}

这是您需要的吗？