Question

我有两张桌子

@Entity
@Table(name = "TAX_CATEGORY")
public class TaxCategory {

    @Id
    @GeneratedValue
    @Column(name = "ID", nullable = false)
    private long id;

    @Column(name = "CATEGORY", nullable = false)
    private String category;

    @Column(name = "TAX", nullable = false)
    private Double tax; 

@Entity
@Table(name = "PRODUCT")
public class Product {

    @Id
    @GeneratedValue
    @Column(name = "ID", nullable = false)
    private long id;

    @Column(name = "PRICE", nullable = false)
    private Double price;

    @Column(name = "NAME", nullable = false)
    private String name;

    @OneToOne
    @JoinColumn(name = "TAX_CATEGORY_ID")   
    private TaxCategory taxCategory;

现在我想查询

"Select p.name, p.price, t.tax from Product p, TaxCategory t join p.taxCategory.id=t.id"

所以列表它会返回 ProductName ProductPrice Tax

但我无法从两个表中获取此数据。单表数据工作正常。

public interface CustomRepositoryCustom {
    public void customMethod();
}

public interface CustomRepository
    extends JpaRepository<Account, Long>, CustomRepositoryCustom { }

public class CustomRepositoryImpl implements CustomRepositoryCustom {


    public void customMethod() { 
        Query nativeQuery = entityManager.createNativeQuery("Select p.name, p.price, t.tax from Product p, TaxCategory t join p.taxCategory.id=t.id");
        return query.getResultList();
    }
}

抛出异常，即对象不是托管bean。如果我创建自定义对象，那么它也会提供类似的问题。

Answer 1

使用以下JPA查询获取两个表数据。这里使用jpa查询来获取产品。从product对象中，可以获得taxCategory。

public interface CustomRepository extends JpaRepository<Account, Long>, CustomRepositoryCustom {

    Query("select product from Product as product join fetch product.taxCategory as taxCategory where taxCategory.id = :taxCategoryId")
    public Product getProductByCategory(@Param Long taxCategoryId);
}

Answer 2

您可以直接定义JPA方法，而不是查询方法，以根据类别ID查找产品。

@Repository
@RepositoryRestResource
public interface ICountryRepository extends JpaRepository<Product , Long > {
List<Product> findByTaxCategory_Id(@Param Long Id);
}

如何从spring数据jpa中的表中获取数据？

2 个答案: