java - 错误类异常 : Object [id=null] was not of the specified subclass

Question

我有一个像下面这样的模型:

@Entity(name = "request")
public class VisitRequest {
  @Id
  @GeneratedValue
  private Long id;

  @OneToMany(mappedBy = "visitRequest", cascade = CascadeType.ALL, orphanRemoval = true)
  @JsonManagedReference
  private List<Visitor> visitors;

  //default constructor, getters and setters
}

@Entity
@Inheritance(strategy = InheritanceType.JOINED)
@JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "class")
public class Visitor {
  @Id
  @GeneratedValue
  private Long id;

  @ManyToOne
  @JsonBackReference
  private VisitRequest visitRequest;

  //default constructor, getters and setters

}

@Entity
public class ContactPerson extends Visitor {

  private PhoneNumber phoneNumber;

  //default constructor, getters and setters

}

但是当我尝试通过与联系人交换其中一位访客来更新 visitRequest 并尝试在 CRUD 存储库上执行该方法时 visitRequestRepository.save(visitRequest);我收到此异常:

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.orm.ObjectRetrievalFailureException: Object [id=null] was not of the specified subclass [cern.ais.visits.core.domain.visitor.Visitor] : class of the given object did not match class of persistent copy; nested exception is org.hibernate.WrongClassException: Object [id=null] was not of the specified subclass [cern.ais.visits.core.domain.visitor.Visitor] : class of the given object did not match class of persistent copy] with root cause

也许问题在于数据库中的 contact_person 和 visitor 表中使用了相同的 ID？

我该如何解决这个问题？我已经搜索了解决方案，但没有一个对我有用。

Answer 1

您可能没有在 ContactPerson 中初始化 visitRequest 引用。请看下面的配置，它适用于 Spring Boot JPA。我用过lombok生成 Getter 和 Setter。

这是一个在 Spring Boot 中实现的工作示例 https://github.com/ConsciousObserver/SpringBootJpaInheritance

@Data
@Entity(name = "request")
class VisitRequest {
    @Id
    @GeneratedValue
    private Long id;

    @OneToMany(mappedBy = "visitRequest", cascade = CascadeType.ALL, orphanRemoval = true)
    @JsonManagedReference
    private List<Visitor> visitors = new ArrayList<>();
}

@NoArgsConstructor
@Data
@Entity
@Inheritance(strategy = InheritanceType.JOINED)
@JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "class")
class Visitor {
    @Id
    @GeneratedValue
    private Long id;

    @ManyToOne
    @JsonBackReference
    private VisitRequest visitRequest;

    public Visitor(VisitRequest visitRequest) {
        this.visitRequest = visitRequest;
    }
}

@NoArgsConstructor
@Data
@ToString(callSuper = true)
@EqualsAndHashCode(callSuper = true)
@Entity
class ContactPerson extends Visitor {
    private String phoneNumber;

    public ContactPerson(VisitRequest visitRequest, String phoneNumber) {
        super(visitRequest);
        this.phoneNumber = phoneNumber;
    }
}