如何获取带有判别器列值的Hibernate继承类型SingleTable的整行？

Question

我有一个父类电子和子类照相机和移动。我使用Hibernate继承单表类型。我想得到所有的电子产品和他们的产品类型，但在获取，我无法得到的产品类型，这也是鉴别列。这是我第一个使用springboot和hibernate的项目。如能提供任何帮助，将不胜感激。

电子类

@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@Table(name = "electronics")
@DiscriminatorColumn(name = "product_Type", discriminatorType = DiscriminatorType.STRING)
public class Electronics {

    @Id
    @GenericGenerator(name = "CamIdGenerator", strategy = "com.virtusa.neuralhack.vlx.IdGenerator.CameraIdGenerator")
    @GeneratedValue(generator = "CamIdGenerator")
    @Column(name = "product_id")
    private String productId;
    
    private String askingPrice;

    @Column(name = "age")
    private String howOld;

    @Column(name = "model")
    private String model;

    @Column(name = "brand")
    private String brand;

    @Column(name = "description")
    private String description;

    transient private String email;
    \\ getters and setter

电子存储库

@Override
    public List<Electronics> getDefaultElectronicProducts() {

        //System.out.println("repo check 1");
        Session currentSession = manager.unwrap(Session.class);
        
        //Query<Electronics> query = currentSession.createQuery("Select * from electronics Order By Rand() Limit 6", Electronics.class);
    
        //System.out.println("repo check 2");
        
        String query = "FROM Electronics ORDER BY RAND()";
        
        Query<Electronics> q =(Query<Electronics>) manager.createQuery(query,Electronics.class);
        
        q.setMaxResults(5);
        
        List<Electronics> defaultProductList = q.getResultList();
        
        //System.out.println("repo check 3");
        
        //System.out.println(defaultProductList.get(1));
        
        return defaultProductList;
    }

Answer 1

我想您已经用包含产品类型值的@DiscriminatorValue注释正确地注释了子类？在这种情况下，检查结果列表中的对象类型。您将看到，根据数据库中的值，您将得到子类的实例。你就是这样找出类型的。我认为您也可以在@Column(name = "product_Type", insertable = false, updatable = false)实体中将产品类型建模为Electronics，但我不建议这样做，以避免对实际值的可能混淆。