有可能调用原生查询并将结果集存储在非实体对象中吗？

Question

我试图使用本机查询获得一个非实体对象，我想将其用作应用程序中一个页面上视图的模型。我遵循这个解释，它没有太多细节，它更像是一张备忘单，写给已经熟悉这个主题的人，只需要提醒。很多年前这里和这里都有类似的问题，因为我不知道所提供的代码块应该放在哪里，我想我可能会问一个新问题。无论我尝试什么，我都会遇到以下例外：

org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type [org.springframework.data.jpa.repository.query.AbstractJpaQuery$TupleConverter$TupleBackedMap] to type

这是我的模型类：

public class ProductForHomeView {

    private int id;
    private String title;
    private EProductType productType;
    private double price;
    private int quantity;

    public ProductForHomeView(int id, String title, EProductType productType, double price, int quantity) {
        this.id = id;
        this.title = title;
        this.productType = productType;
        this.price = price;
        this.quantity = quantity;
    }

存储库界面：

public interface IProductsRepository extends CrudRepository<Products, Integer> {
    @Query(value = "SELECT products.id, products.title, products.the_type AS productType, stock.price, stock.quantity FROM products LEFT JOIN stock on products.id=stock.product_id", nativeQuery = true)
    List<ProductForHomeView> getProductsInfoForTheHomePage();   
}

以及我尝试映射非实体类的实体类之一：

@Entity
@Table(name = "stock")
@SqlResultSetMapping(
        name="ProductForHomeViewMapping",
        classes={
        @ConstructorResult(
        targetClass=qualified.name.ProductForHomeView.class,
        columns={
        @ColumnResult(name="id", type=Integer.class),
        @ColumnResult(name="title", type=String.class),
        @ColumnResult(name="productType", type=EProductType.class),
        @ColumnResult(name="price", type=Long.class),
        @ColumnResult(name="quantity", type=String.class)
        })})
public class Stock {
// mapped fields, constructors, geters and setters...
}

我感谢任何输入！

Answer 1

我使用了@SqlResultSetMapping和@NamedNativeQuery

使用以下内容更改您的凝乳储存库方法

public interface IProductsRepository extends CrudRepository<Products, Integer> {
    @NamedNativeQuery(value = "SELECT products.id, products.title, products.the_type AS productType, stock.price, stock.quantity FROM products LEFT JOIN stock on products.id=stock.product_id", resultSetMapping = "ProductForHomeViewMapping")
    List<ProductForHomeView> getProductsInfoForTheHomePage();   
}

更多信息请点击此处

Answer 2

您可以将视图声明为一个接口，然后Spring Data将按照您想要的方式处理它。

以下是示例：

https://github.com/roberthunt/spring-data-native-query-projection/blob/master/src/main/java/uk/co/rbrt/PersonSummary.java

https://github.com/roberthunt/spring-data-native-query-projection/blob/master/src/main/java/uk/co/rbrt/PersonRepository.java