休眠-从多个字段到同一实体的关系

Question

我有实体FooDetails，它具有两个字段：客户和位置列表。 客户具有地址（@OneToOne单向映射），而位置也具有具有@OneToOne映射的地址。

碰巧“客户”和“位置”中的“地址”相同。 所有这些对象都来自远程服务，在保存之前，我手动将远程对象的ID放入实体中。 映射如下所示：

@Entity
@Table(name = "FOO")
public class FooDetails {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private long id;

    @OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @JoinColumn(name = "customer_id")
    private Customer customer;

    @OneToMany(cascade = CascadeType.ALL)
    @JoinColumn(name = "details_id")
    private Set<Location> locationList;
...
}

@Entity
@Table(name = "CUSTOMER")
public class Customer {

    @Id
    @Column(name = "customer_id", unique = true)
    private long customerId;

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

@Entity
@Table(name = "LOCATION")
public class Location {

    @Id
    @Column(name = "location_id", unique = true)
    private long locationId;

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

@Entity
@Table(name = "ADDRESS")
public class Address{

    @Id
    @Column(name = "address_id")
    private long addressId;
    ...

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof StawareAddress)) return false;

        StawareAddress that = (StawareAddress) o;

        return addressId == that.addressId;
    }

    @Override
    public int hashCode() {
        return (int) (addressId ^ (addressId >>> 32));
    }
}

当我从Web服务接收整个FooDetails对象时，我尝试将其保存到本地数据库。

如果数据库是干净的（尚未保存地址），则会保存一个来自WS且具有正确ID的地址。 如果已经有一个具有此ID的地址，则Hibernate会尝试将新的ID插入数据库，并且由于对addressId的唯一约束，将出现错误。

我正在使用Spring Data Jpa保存实体（save（）方法）。

我错过了哪些明显的实体映射问题？

Answer 1

我实际上不鼓励在这里使用CascadeType.ALL并手动处理它。

public void saveFoodetails(FooDetails fooDetails) {
  Address address = addressRepository.find( fooDetails.getAddress().getId() );
  if ( address != null ) {
    // perhaps you update address with data from fooDetails.getAddress()
    addressRepository.save( address );
    // associate attached address instance with fooDetails now.
    fooDetails.setAddress( address );
  }
  else {
    // save the new incoming address contained in FooDetails
    addressRepository.save( fooDetails.getAddress() );
  }
  // now save/update FooDetails
  fooDetailsRepository.save( fooDetails );        
}