Spring Data JPA：如何在countQueries中重复自己？

Question

我正在使用Spring Data JPA存储库（1.7.2），我通常面临以下情况：

• 实体具有延迟加载的集合
• 有时会急切地获取这些集合（通过JPAQL fetch join ）
• 存储库通常返回Page<Foo>而不是List<Foo>

我需要为每个在返回Page的存储库上使用fetch join的@Query提供countQuery 。 此StackOverflow问题已讨论过此问题

我的典型存储库方法如下所示：

@Query(value = "SELECT e FROM Employee e LEFT JOIN FETCH e.addresses a " +
    "WHERE e.company.id = :companyId " +
    "AND e.deleted = false " +
    "AND e.primaryAddress.deleted = false " +
    "ORDER BY e.id, a.id",
    countQuery="SELECT count(e) FROM Employee e WHERE e.companyId = :companyId AND e.deleted = false AND e.primaryAddress.deleted = false"
)
Page<Employee> findAllEmployeesWithAddressesForCompany(@Param("companyId") long companyId, Pageable pageable);

显然， 它不是很干 。 您可以告诉我正在重复value和countQuery参数中的所有条件。 我怎么待在这里干？

Answer 1

你可以这样做

public interface MyRepository extends JpaRepository {

    public static final String WHERE_PART = "e.companyId = :companyId AND e.deleted = false AND e.primaryAddress.deleted = false ";

    @Query(value = "SELECT e FROM Employee e LEFT JOIN FETCH e.addresses a " +
        "WHERE " + MyRepository.WHERE_PART
        "ORDER BY e.id, a.id",
        countQuery="SELECT count(e) FROM Employee e WHERE " + MyRepository.WHERE_PART
    )
    Page<Employee> findAllEmployeesWithAddressesForCompany(@Param("companyId") long companyId, Pageable pageable);