java - JPA 实体扩展类包含@Id

Question

我有实体类都包含 id 作为主键，我可以创建包含所有公共(public)字段的抽象类并允许所有类扩展此类，如下所示:

public abstract class CommonFields{
    @Id
@Column(name = "ID")
private long id;

public void setId(long id) {
    this.id = id;
}

public long getId() {
    return id;
}
}

@Entity
    @Table
    public class B extends CommonFields{
    String carModel;
}




@Entity
    @Table
    public class A extends CommonFields{
    String name;
}

谢谢大家

Answer 1

您可以使用@MappedSupperclass 对类的公共(public)字段进行注释

@MappedSuperclass
public abstract class CommonFields{
    @Id
    @Column(name = "ID")
    private long id;

    public void setId(long id) {
        this.id = id;
    }

    public long getId() {
        return id;
    }
}

来自@MappedSuperclass 文档:

Designates a class whose mapping information is applied to the entities that inherit from it. A mapped superclass has no separate table defined for it.