如何将sql本机查询结果映射到spring jpa存储库中的DTO？

Question

嗨，我想要实现的是在 java spring jpa 存储库中将 SQL 本机查询结果映射到我的 DTO，我该如何正确地做到这一点？我尝试了几个代码，但它不起作用，这是我尝试过的：

第一次尝试：

@Repository
public interface StockRepository extends RevisionRepository<Stock, Long, Integer>, JpaRepository<Stock, Long> {
    
   @Query(value = "SELECT stock_akhir.product_id AS productId, stock_akhir.product_code AS productCode, SUM(stock_akhir.qty) as stockAkhir "
        + "FROM book_stock stock_akhir "
        + "where warehouse_code = (:warehouseCode) "
        + "AND product_code IN (:productCodes) "
        + "GROUP BY product_id, product_code, warehouse_id, warehouse_code", nativeQuery = true)
   List<StockAkhirDto> findStockAkhirPerProductIn(@Param("warehouseCode") String warehouseCode, @Param("productCodes") Set<String> productCode);
}

一旦我执行了这个函数，我得到了这个错误：

没有找到能够从类型转换的转换器 [org.springframework.data.jpa.repository.query.AbstractJpaQuery$TupleConverter$TupleBackedMap] 输入 [com.b2bwarehouse.Dto.RequestDto.StockDto.StockAkhirDto]

第二次尝试：

@Repository
public interface StockRepository extends RevisionRepository<Stock, Long, Integer>, JpaRepository<Stock, Long> {
    
   @Query(value = "SELECT new com.b2bwarehouse.Dto.RequestDto.StockDto.StockAkhirDto(stock_akhir.product_id AS productId, stock_akhir.product_code AS productCode, SUM(stock_akhir.qty) as stockAkhir) "
      + "FROM book_stock stock_akhir "
      + "where warehouse_code = (:warehouseCode) "
      + "AND product_code IN (:productCodes) "
      + "GROUP BY product_id, product_code, warehouse_id, warehouse_code", nativeQuery = true)
   List<StockAkhirDto> findStockAkhirPerProductIn(@Param("warehouseCode") String warehouseCode, @Param("productCodes") Set<String> productCode);
}

第二个是错误：

无法提取结果集； SQL [不适用]；嵌套异常是 org.hibernate.exception.SQLGrammarException：无法提取 结果集

下面是我的 DTO：

@Data
@AllArgsConstructor
@NoArgsConstructor
public class StockAkhirDto {
   private Long productId;
   private String productCode;
   private Integer stockAkhir;
}

我应该如何更正我的代码？那么，我可以将结果放入我的 DTO 中吗？

Answer 1

您可以使用适当的 sql 结果集映射定义以下命名本机查询：

import javax.persistence.NamedNativeQuery;
import javax.persistence.SqlResultSetMapping;
import javax.persistence.ConstructorResult;
import javax.persistence.ColumnResult;

@Entity
@NamedNativeQuery(
    name = "find_stock_akhir_dto",
    query =
        "SELECT " + 
        "  stock_akhir.product_id AS productId, " + 
        "  stock_akhir.product_code AS productCode, " + 
        "  SUM(stock_akhir.qty) as stockAkhir " + 
        "FROM book_stock stock_akhir " + 
        "where warehouse_code = :warehouseCode " + 
        "  AND product_code IN :productCodes " + 
        "GROUP BY product_id, product_code, warehouse_id, warehouse_code",
    resultSetMapping = "stock_akhir_dto"
)
@SqlResultSetMapping(
    name = "stock_akhir_dto",
    classes = @ConstructorResult(
        targetClass = StockAkhirDto.class,
        columns = {
            @ColumnResult(name = "productId", type = Long.class),
            @ColumnResult(name = "productCode", type = String.class),
            @ColumnResult(name = "stockAkhir", type = Integer.class)
        }
    )
)
public class SomeEntity
{
}

然后使用它：

@Repository
public interface StockRepository extends RevisionRepository<Stock, Long, Integer>, JpaRepository<Stock, Long> {

   @Query(name = "find_stock_akhir_dto", nativeQuery = true)
   List<StockAkhirDto> findStockAkhirPerProductIn(
      @Param("warehouseCode") String warehouseCode,
      @Param("productCodes") Set<String> productCode
   );
}

Answer 2

我找到了一种不常见的方法，但是当我尝试使用 QueryDsl 来解决这个问题时，我发现了一种名为 “Tuple” 的数据类型，但如果你只是一个人，我不会推荐 QueryDsl像我一样开始。让我们专注于我如何使用 "Tuple"

我将返回类型更改为 Tuple，这是我的存储库的样子：

@Repository
public interface StockRepository extends RevisionRepository<Stock, Long, Integer>, JpaRepository<Stock, Long> {
    
   @Query(value = "SELECT stock_akhir.product_id AS productId, stock_akhir.product_code AS productCode, SUM(stock_akhir.qty) as stockAkhir "
        + "FROM book_stock stock_akhir "
        + "where warehouse_code = (:warehouseCode) "
        + "AND product_code IN (:productCodes) "
        + "GROUP BY product_id, product_code, warehouse_id, warehouse_code", nativeQuery = true)
   List<Tuple> findStockAkhirPerProductIn(@Param("warehouseCode") String warehouseCode, @Param("productCodes") Set<String> productCode);
}

然后在我的服务类中，由于它作为元组返回，我必须手动一一映射列，这是我的服务函数的样子：

public List<StockTotalResponseDto> findStocktotal() {
    List<Tuple> stockTotalTuples = stockRepository.findStocktotal();
    
    List<StockTotalResponseDto> stockTotalDto = stockTotalTuples.stream()
            .map(t -> new StockTotalResponseDto(
                    t.get(0, String.class), 
                    t.get(1, String.class), 
                    t.get(2, BigInteger.class)
                    ))
            .collect(Collectors.toList());
    
    return stockTotalDto;
}

列字段以 0 开头，这样我可以在存储库级别保持查询整洁。但我会接受 SternK 的答案作为接受的答案，因为这种方式也很有效，如果有人需要这样的东西，我会在这里保留我的答案

Answer 3

创建标准原生@Query

@Query(value = "select id, age, name FROM Person WHERE age=?1", nativeQuery=true)
List<PersonView> getPersonsByAge(int age);

还有一个界面

public interface PersonView {
    Long getId();
    Integer getAge();
    String getName();
}

列按顺序匹配（而不是按名称）。 这样，您就有了一个原生查询，没有实体，也没有太多样板代码（也就是很多注释）。

但是，结果视图（Jdk 代理等）的访问速度非常慢，我有一些代码对流进行了一些分组，它是 10 倍！比标准 DTO/Pojos 慢！ 所以最后，我不再使用 nativeQuery 了，但是：

SELECT new com.my_project.myDTO(p.id, p.age, p.name) .....

Answer 4

第二个变体非常接近。您只需删除构造函数表达式的别名：

new com.b2bwarehouse.Dto.RequestDto.StockDto.StockAkhirDto(
    stock_akhir.product_id, 
    stock_akhir.product_code, 
    SUM(stock_akhir.qty)
)

应该可以。

Answer 5

基于 Sternk 答案的另一个有效选项如下

您可以使用适当的 sql 结果集映射定义以下命名本机查询：

资源/META-INF/orm.xml

<?xml version="1.0" encoding="UTF-8"?>
<entity-mappings xmlns="http://java.sun.com/xml/ns/persistence/orm"
                 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                 xsi:schemaLocation="http://java.sun.com/xml/ns/persistence/orm http://java.sun.com/xml/ns/persistence/orm_2_0.xsd"
                 version="2.0">
    <named-native-query name="find_stock_akhir_dto" result-class="com.fullyqualified.name.SomeEntity"
                        result-set-mapping="stock_akhir_dto">
        <query><![CDATA[
            SELECT 
              stock_akhir.product_id AS productId, 
              stock_akhir.product_code AS productCode, 
              SUM(stock_akhir.qty) as stockAkhir 
            FROM book_stock stock_akhir 
            where warehouse_code = :warehouseCode 
              AND product_code IN :productCodes  
            GROUP BY product_id, product_code, warehouse_id, warehouse_code]]></query>
    </named-native-query>
</entity-mappings>

import javax.persistence.NamedNativeQuery;
import javax.persistence.SqlResultSetMapping;
import javax.persistence.ConstructorResult;
import javax.persistence.ColumnResult;

@Entity
@SqlResultSetMapping(
    name = "stock_akhir_dto",
    classes = @ConstructorResult(
        targetClass = StockAkhirDto.class,
        columns = {
            @ColumnResult(name = "productId", type = Long.class),
            @ColumnResult(name = "productCode", type = String.class),
            @ColumnResult(name = "stockAkhir", type = Integer.class)
        }
    )
)
public class SomeEntity
{
}

然后使用它：

@Repository
public interface StockRepository extends RevisionRepository<Stock, Long, Integer>, JpaRepository<Stock, Long> {

   @Query(name = "find_stock_akhir_dto", nativeQuery = true)
   List<StockAkhirDto> findStockAkhirPerProductIn(
      @Param("warehouseCode") String warehouseCode,
      @Param("productCodes") Set<String> productCode
   );
}