Returned object from Spring Data Jpa query has null values

Question

I'm trying to get object of custom type from JPA Repository

VisitRepository.java

@Repository
public interface VisitRepository extends JpaRepository<Visit, Long>, JpaSpecificationExecutor<Visit> {
    @Query(value = "select client_id , count(*) from visit  where (DATE(jhi_date) between :startDate and :endDate) group by client_id",nativeQuery = true)
    List<IIntegerReportData> findByDate(@Param("startDate") String startDate, @Param("endDate") String endDate);

IIntegerReportData.java

package com.mycompany.hiptest.repository;

public interface IIntegerReportData {
    Long getId();
    Integer getValue();
}

ClientRating.java

 public List<ClientsRatingDTO> findAllSorted(String startDate, String endDate, Long fieldNum) {
        List<IIntegerReportData> visitReport = visitRepository.findByDate(startDate, endDate);   
        log.debug("visitReport:" + visitReport.size());

        for (IIntegerReportData visit : visitReport
        ) {
            log.debug("value: " + visit.getValue());
          }

In debug i get visitReport.size() = 27 (that is correct records count), but
visit.getValue() is NULL for each rows, although there are not null values in this field for each rows. What's wrong?

Answer 1

You could use NativeQuery Annotation:

Have a look at:

https://www.baeldung.com/spring-data-jpa-query

Answer 2

When returning a custom object from a native query, the result column names must match the names of the custom interface, otherwise they'll just have null values. Eg:

@Repository
public interface MyRepository extends JpaRepository<MyEntity, Long> {
    @Query(value = "SELECT "\"id\" FROM \"my_entity\"", nativeQuery = true)
    List<IdNative> findAllIdNative();

    interface IdNative {
        Long getEntityId();
    }
}

Here, getEntityId() will always return null because the result table of the query has no entityId column. To fix, either change the query to match the method:

SELECT "id" AS "entityId" FROM "my_entity"

Or, change the interface method to match the column name:

Long getId();