JPA实体扩展类包含@Id [英] JPA entity extends class contain @Id

问题描述

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

i have entities classes all contains id as primary key, can i create abstract class which contains all common fields and allow all classes extends this class as the following :

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

推荐答案

您可以使用@MappedSupperclass的公共字段注释类

You can annotate the class with the common fields with @MappedSupperclass

@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 doc：

From the @MappedSuperclass doc:

指定一个类，其映射信息应用于从中继承的
实体。映射的超类没有为其定义单独的
表。

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.

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