Question

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）并添加同一公司作为供应商和买家时，我看到 'Multiple representations of the same entity'。

我读过this但没有任何帮助。当我删除CascadeType.All我得到

'detached entity passed to 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？

更新

首先我在@ManyToOne(Cascade.All)

中将@ManyToOne()更改为DocumentDetails

第二我在@ManyToOne(Cascade.All)中将@ManyToOne(Cascade.Merge)更改为DocumentDetails。

第三，我在@ManyToOne(Cascade.All)中将@ManyToOne(all types except all and merge)更改为DocumentDetails。

我也尝试使用Address类

Answer 1

好的 - 从Piotr Gwiazda的提示我解决了它。

简单而天真的解决方案是：

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

。这种情况发生了，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。

Answer 2

当您使用相同的值覆盖对象时会发生这种情况不同的哈希码，如果我有员工类，员工是拥有地址如果我将保存具有相同地址值但具有不同哈希码的同一员工，那么我将得到此问题，如果我愿意的话克隆地址并在员工中设置然后Hibernate会感到困惑无法保存数据

@Entity
@Getter
@Setter
class Person implements Serializable {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(name="id", unique = true, nullable = false)
    private Long id;

    @OneToMany(cascade= CascadeType.ALL)
    private Set<Address> Addresses = new HashSet<>();

    protected Person(){}
}

@Entity
@Getter
@Setter
class Address implements Serializable {
    @EmbeddedId
    private AddressId addressId;
    private State state;
    protected Address(){}
}

@Embeddable
@Getter
@Setter
public class AddressId implements Serializable {
    @Column(name = "person_id")
    private Long personId;
    @Column(name = "postcode")
    private String postcode;
}

解决方案

AddressId addressId = new AddressId();
addressId.setPersonId(personId);
addressId.setPostcode("4000"); //person already has an address with this postcode
Address address = null;
for (Address a : person.getAddresses()) {
    if (a.getAddressId().equals(addressId)) {
        address = a;
        break;
    }
}
if (address == null) {
    address = new Address();
    address.setAddressId(addressId);
    address.setState(State.ABC); //but I want to change the state from QLD to TAS
    person.getAddresses().add(address);
}
else {
    address.setState(State.TAS);
}
person = personRepo.save(person);

JPA / Hibernate同一实体的多个表示

2 个答案: