我对 JPA 继承有疑问。数据库模型也是专门搭建的。它包含几个具有相同属性的表（这些表是故意按国家/地区切割的），并且所有这些表都连接到另一个表（OneToOne）。
以下是数据模型的示例：usa_user、Germany_user、austria_user。所有这些表都具有相同的属性（id、name、address）。现在地址也是根据国家建立的，例如usa_address、Germany_address、austria_address。
现在我不知道或有问题，我已经正确映射了很长时间。我有以下内容：
// All Lombok Getter, Setter Args,...
@MappedSuperclass
public abstract Address {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@JsonIgnore
private Long id;
@OneToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "user_id", referencedColumnName = "id")
@JsonIgnore
private User user;
private String name;
private String addr_num;
...
}
// All Lombok Getter, Setter Args,...
@MappedSuperclass
public abstract User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@JsonIgnore
private Long id;
@OneToOne(mappedBy = "user", cascade = CascadeType.ALL, fetch = FetchType.LAZY, optional = false)
@JsonIgnore
private Address address;
private String name;
}
@Entity
@Table(name = "usa_user")
public class UsaUser extends User {}
@Entity
@Table(name = "austria_user")
public class AustriaUser extends User {}
@Entity
@Table(name = "germany_user")
public class GermanyUser extends User {}
@Entity
@Table(name = "usa_address")
public class UsaAddress extends Address {}
@Entity
@Table(name = "austria_address")
public class AustriaAddress extends Address {}
@Entity
@Table(name = "germany_address")
public class GermanyAddress extends Address {}
But unfortunately this does not work. Every time I start it JPA notices that it can't map the Entities Address - User (which is understandable because they are not entities but abstract classes). What would be the best way to solve this? I want to avoid that I have to list the attributes in all these entities because it would be redundant.
The goal is to find out how I can use a @MappedSuperclass in a @MappedSuperclass.