Springboot jpa使用sum()函数返回结果如何被接收

@Repository
public interface UrlsRepository extends JpaRepository<Urls, String> { 
    Optional<Urls> findById(Integer id);
}

    @Query(value = "SELECT domain,sum(visit_count) from Urls GROUP BY domain ORDER BY sum(visit_count) desc", nativeQuery = true)
    List<Object[]> findDomainAndCount();

    @Test
    public void findDomainAndCount() {
        List<Object[]> list = urlsRepository.findDomainAndCount();
        for (Object[] objs : list) {
            for (int i = 0; i < objs.length; i++) {
                System.out.print(String.valueOf(objs[i]) + ",");
            }
            System.out.println();
        }
    }

@Getter
@Setter
@ToString
public class DomainVo {
    private String domain;
    private Long visitCount; 
    public DomainVo(String domain, Long visitCount) {
        this.domain = domain;
        this.visitCount = visitCount;
    }
}

    /*
    注意：
    1、使用的是全类名
    2、查询的表对应的是已经绑定的实体类Urls
    3、nativeQuery设为false，表示使用的是jpql语言。
     */ 
@Query(value = "SELECT new com.ununie.chromehistory.model.vo.DomainVo(u.domain,sum(u.visitCount)) from Urls u GROUP BY u.domain ORDER BY sum(u.visitCount) desc")
    List<DomainVo> findDomainCount();

    @Test
    public void findDomainCount() {
        List<DomainVo> domainCount = urlsRepository.findDomainCount();
        for (DomainVo vo : domainCount) {
            System.out.println(vo);
        }
    }

public long getObjectsCountByQueryString(String queryString) {
        //queryString = "select count(o) from MyModel as o"; 
        long count = 0; 
        count = ((Long)getJpaTemplate().find(queryString).get(0)).longValue();
        return count; 
    }      
    public long getObjectsSumByQueryString(String queryString) {
        //queryString = "select sum(o.price) from MyModel as o"; 
        List list = getJpaTemplate().find(queryString);
        //使用sum函数要注意这里要先判断是否为null，不然会出空指针异常，count函数不用判断null
        if(list.get(0) == null){
            return 0;
        }
        else{
            return ((Long)list.get(0)).longValue();
        }
    }

@Query(" select count(t) from FollowerInfo t where investUserId = :invUserId")
Integer findFollowerNumberByInvUserId(@Param("invUserId") Long invUserId);

List findAll(Specification spec);

/**
* Returns the number of entities available.
*
* @return the number of entities
*/
long count();

Long countByInvestUserId(Long investUserId);