JPA mapping native query result to non entity DTO

Question

I have a complex native query and I am trying to map its result to a non-entity DTO class. I am trying to use JPA's SqlResultSetMapping with ConstructorResult

My DTO class

@Data
public class Dto {

    private Long id;

    private String serial;

    private Long entry;

    private int numOfTasks;
}

My entity class, which has the repository interface that I will call this native query result.

@SqlResultSetMapping(
        name = "itemDetailsMapping",
        classes = {
                @ConstructorResult(
                        targetClass = Dto.class,
                        columns = {
                                @ColumnResult(name = "ID"),
                                @ColumnResult(name = "SERIAL"),
                                @ColumnResult(name = "ENTRY"),
                                @ColumnResult(name = "TASKS")
                        }
                )
        }
)

@NamedNativeQuery(name = "getItemDetails", query = "complex query is here", resultSetMapping = "itemDetailsMapping")
@Entity
@Data
public class Item {}

Repository

@Repository
public interface ItemRepository extends JpaRepository<Item, Long> {

    ...     

    List<Dto> getItemDetails();

}

When I call the getItemDetails() from ItemRepository I have the following error:

org.springframework.data.mapping.PropertyReferenceException: No property itemDetails found for type Item

What is the proper way to use SqlResultSetMapping and ConstructorResult and solve this problem.

Any help would be appreciated.

Answer 1

To use named queries the name of the named query must have the entity name as prefix:

@NamedNativeQuery(name = "Item.getItemDetails", 
                 query = "complex query is here", resultSetMapping = "itemDetailsMapping")

Then the interface method must have the same name as the named query without the prefix:

List<Dto> getItemDetails();

-

Read more about Spring Data JPA and named queries in the reference doc https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#jpa.query-methods.named-queries