JPA / Hibernate同一实体的多个表示

2019年7月20日 166次阅读

我的实体：

@Entity
public class Document  {

   @Id
   protected String id; //It string in purpose

   @OneToOne(cascade = ALL)
   @JoinColumn(name = "DOCUMENT_DETAILS")
   private DocumentDetails details;

} 

@Entity
@Inheritance(strategy = InheritanceType.JOINED)
@DiscriminatorColumn(name = "documentDiscr")
@EqualsAndHashCode
public abstract class DocumentDetails {

   @Id @GeneratedValue(strategy = GenerationType.SEQUENCE)
   private Long id;

   private Money total;

   @ManyToOne(cascade = CascadeType.ALL)
   @JoinColumn(name = "SELLER_ID")
   private Company seller;

   @ManyToOne(cascade = CascadeType.ALL)
   @JoinColumn(name = "BUYER_ID")
   private Company buyer;
}

@Entity
public class Company {

   @Id
   protected String id;

   private String name;
   private String phoneNumber;
   private String email;

   @OneToOne(cascade = CascadeType.ALL)
   @JoinColumn(name = "address_id")
   private Address address;
}

@Entity
@EqualsAndHashCode
public class Address {

   @Id
   @GeneratedValue(strategy= GenerationType.SEQUENCE)
   private Long id;
   private String country;
   private String city;
   private String postalCode;
   private String streetName;
   private String streetNumber;
   private String apartmentNumber;
}

@Path("path")
@Transactional 
public class MyResource {

   @Inject
   MyRepo myRepo;

   @PUT
   public Document updateDoc(Document document){
       myRepo.update(document);
   }

}

public class Repo<T extends MyClass> implements MyRepo<T> {

    @PersistenceContext
    protected EntityManager entityManager;


    public T create(T t) {
       t.generateId();
       this.entityManager.persist(t);
       return t;
    }

    public T update(T entity) {
       return entityManager.merge(entity);
    }

}

当我调用entityManage.update(documentEntity)并将同一公司作为供应商和买家添加时,我看到了
‘同一实体的多重表示’.

我读了this,但没有任何帮助.当我删除CascadeType.All我得到

‘分离的实体传递给persist：my.pckg.Address’

我也尝试删除CascadeType.Merge但错误是一样的.
我可以做什么？我的错误在哪里？

UPDATE

首先,我将@ManyToOne(Cascade.All)更改为DocumentDetails中的@ManyToOne()

其次,我将@ManyToOne(Cascade.All)更改为DocumentDetails中的@ManyToOne(Cascade.Merge).

第三,我在DocumentDetails中将@ManyToOne(Cascade.All)更改为@ManyToOne(除了all和merge之外的所有类型).

我也尝试使用Address类

最佳答案 好的 – 从Piotr Gwiazda的提示我解决了它.

添加简单而天真的解决方案：

if(seller != null && buyer != null){
   if(seller.equals(buyer)){
       document.getDetails.setSeller(document.getDetails().getBuyer());
   }
}

(更好的答案是SpringData)

在update()之前.这种情况已经到位,因为当两个不同的对象相等但它们引用不同时,hibernate无法将它们作为同一个对象处理.

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