我们可以从@Embedded类扩展@Entity类(Can we extends @Entity class from @Embedded class)

@Embeddable
@MappedSuperclass
public class Address {
  private String street;
  private String city;

public String getStreet(){ return street;}
public String getCity(){ return city;}
public String setStreet(Sting street){ this.street= street;}
public String setCity(String city){ this.city=city;}

}

import org.hibernate.annotations.Entity;
@Entity
public class AddressHistory extends Address {
 Long id;
 @Id @XmlTransient
 @GeneratedValue(strategy = GenerationType.AUTO)
  public Long getId() {
    return m_id;
  }

 public void setId(Long m_id) {
    this.m_id = m_id;
 }
}
 
 这是我的场景，我想存储一个人的地址。 而且我还必须存储一个人以前住过的所有地址。 所以我正在做的是我在当前表中嵌入当前地址，并希望将他/她的所有前一个地址存储在历史表中。 为了达成这个。 我将Address类嵌入并嵌入到person表和HistoryAddress表中。 但是从OOPS概念来看。 HistoryAddress是一个Address，因此将Address类的组合写入AddressHistory并不好。 然后我决定从Address类扩展AddressHistory。 当我这样做时，休眠会给我这个错误 
 
Use of @OneToMany or @ManyToMany targeting an unmapped class AddressHistory.
 
 但显然我已经映射了AddressHistory我们可以这样做吗？ 我们可以从嵌入式类扩展实体吗？ 

@Embeddable
@MappedSuperclass
public class Address {
  private String street;
  private String city;

public String getStreet(){ return street;}
public String getCity(){ return city;}
public String setStreet(Sting street){ this.street= street;}
public String setCity(String city){ this.city=city;}

}

import org.hibernate.annotations.Entity;
@Entity
public class AddressHistory extends Address {
 Long id;
 @Id @XmlTransient
 @GeneratedValue(strategy = GenerationType.AUTO)
  public Long getId() {
    return m_id;
  }

 public void setId(Long m_id) {
    this.m_id = m_id;
 }
}
 
Here is my scenario, I want to store address of a person. And I also have to store all the address that a person has live before. So what I am doing is I am embedding current address in person table and would like to store all his/her pervious address in history table. To achieve this. I made Address class embeddable and embedded it into person table and HistoryAddress table. But as of OOPS concept. HistoryAddress is a Address, so it is not good to do composition of Address class into AddressHistory. Then I decided to extends AddressHistory from Address class. BUt when I do this hibernate gives me this error 
 
Use of @OneToMany or @ManyToMany targeting an unmapped class AddressHistory.
 
But clearly I have mapped AddressHistory Can we do this ? Can we extend Entity from Embedded class ?

原文：https://stackoverflow.com/questions/11581718