java - 获取特定列表后，Spring Jpa 删除操作不起作用

Question

这些是我的实体；

@Entity
 public class IpAddress{

    @Id
    @Column(nullable = false, updatable = false)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SEQ")
    @Getter
    private Long id;

     @ManyToOne(fetch = FetchType.LAZY)
     private final Application application;

     .....
 }

@Entity
public class Application{

@Column(nullable = false, updatable = false)
private final String applicationId;

@OneToMany(mappedBy = "application", cascade = CascadeType.ALL, orphanRemoval = true)
private List<IpAddress> ipAddresses = new ArrayList<>();
}

@Entity
public class MerchantApplication {

    @Id
    @Column(nullable = false, updatable = false)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SEQ")
    @Getter
    private Long id;
    @OneToOne
    private final Merchant merchant;

    @OneToOne(cascade = CascadeType.ALL)
    private final Application application;

    @ManyToOne(fetch = FetchType.LAZY)
    private final User user;
}

这是我尝试删除的服务方法:

@Transactional
    public void deleteIpAddressForMerchant(Long merchantId,Long ipAddressId) {

        Merchant merchant = merchantRepository.getMerchant(merchantId);

        MerchantApplication merchantApplication = merchant.getMerchantApplication();

        if (Objects.isNull(merchantApplication))
            throw new ApplicationNotFoundException();

        if (merchantApplication.getApplication().getIpAddresses().size() == 1) {
            throw new IpAddressCannotBeDeleted();
        }

        IpAddress ipAddress = ipAddressRepository.getByIdAndApplication(ipAddressId, merchantApplication.getApplication());
        ipAddressRepository.delete(ipAddress);
    }

当我在服务方法中删除这个 block 时，它工作正常；

if (merchantApplication.getApplication().getIpAddresses().size() == 1) {
            throw new IpAddressCannotBeDeleted();
        }

但是这样不行，你能帮帮我吗，有什么问题吗？

Answer 1

如果您在 @Transactional 方法中获取具有 orphanRemoval = true 属性的实体字段，它将在该方法返回时保存此字段以及您对其所做的更改。

在你的例子中，你获取

merchantApplication.getApplication().getIpAddresses()

但是你没有对它进行任何更改，然后将获取的列表原样保存。

您可以在获取的列表中删除您想要删除的元素。