JPA Repository Native query return custom class instead of Object

Question

In my repository class, I am doing a native query using the @Query annotiation, by only selecting a few fields from MyDomain like this:

@Repository
public interface MyRepository extends JpaRepository<MyDomain, Long> {
    @Query("SELECT q.firstname, q.lastname from MyDomain q WHERE q.firstname = :firstname")
    Page<MyDomain> findByFirstName(String firstname, Pageable pageable);
}

Here is the mapper to convert from MyDomain to Dto and vice versa

@Mapper(componentModel = "spring")
public interface Mapper {

    MyDomainDto toDto(MyDomain data);
    MyDomain fromDto(MyDomainDto data);
}

And then I call this method here in the service:

    private ResponseEntity<List<MyDomainDto>> getByFirstName(String firstname, Pageable pageable) {
        Page<MyDomain> page = dataRepository.findByfirstName(firstname, pageable);
        List<MyDomain> result = page.getContent();

        return new ResponseEntity<>(
                result.stream().map(mapper::toDto).collect(Collectors.toList()), HttpStatus.OK);

When I fetch the result Page<MyDomain> page = dataRepository.findByfirstName(firstname, pageable); it returns a list of Objects instead of my custom class MyDomain.

If I however use the native query like this, by fetching all the data from MyDomain


@Repository
public interface MyRepository extends JpaRepository<MyDomain, Long> {
    @Query("SELECT q from MyDomain q WHERE q.firstname = :firstname")
    Page<MyDomain> findByFirstName(String firstname, Pageable pageable);
}

Then I will get the custom class MyDomain returned by Page<MyDomain> page = dataRepository.findByfirstName(firstname, pageable);

How can I achive the same result when I only fetches a few fields instead of all fields? I tried casting it to MyDomain but no success. Thanks in advance (if anyone is reading this on Saturday)

Bartosz Szymański · Accepted Answer · 2022-11-19 18:06:25Z

1

You can achieve it with fetching your data directly to DTO.

If your DTO class looks like this:

package com.your.project;

public class MyDomainDto {
    private String firstname;
    private String lastname;
    
    public MyDomainDto(String firstname, String lastname) {
        this.firstname = firstname;
        this.lastname = lastname;
    }
}

then you can do it in your repository as follows:

@Repository
public interface MyRepository extends JpaRepository<MyDomain, Long> {
    @Query("SELECT new com.your.project.MyDomainDto(q.firstname, q.lastname) from MyDomain q WHERE q.firstname = :firstname")
    Page<MyDomainDto> findByFirstName(String firstname, Pageable pageable);
}

answered Nov 19, 2022 at 18:06

Bartosz Szymański

4464 silver badges12 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

JPA Repository Native query return custom class instead of Object

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related