Spring Data JPA：如何在countQueries中重復自己？

Question

我正在使用Spring Data JPA存儲庫（1.7.2），我通常面臨以下情況：

• 實體具有延遲加載的集合
• 有時會急切地獲取這些集合（通過JPAQL fetch join ）
• 存儲庫通常返回Page<Foo>而不是List<Foo>

我需要為每個在返回Page的存儲庫上使用fetch join的@Query提供countQuery 。 此StackOverflow問題已討論過此問題

我的典型存儲庫方法如下所示：

@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);

顯然， 它不是很干 。 您可以告訴我正在重復value和countQuery參數中的所有條件。 我怎么待在這里干？

Answer 1

你可以這樣做

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);