pageable+@query+join(fetch?)不起作用

7y4bm7vi  于 2021-07-08  发布在  Java
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我想把分类和 Pageable 关于使用 @Query 来自Spring Data 的注解。
第一个接口的方法(没有 @Query 但是有了 Pageable )很有魅力。就像我只招一个员工 @Query 但不是 Pageable 我在用 Optional<Employee> 有(第三种方法)。但是当我试着把这两个放在一起的时候,乐趣就开始了——它不再起作用了。
当我试图按 name 它尖叫着说这个错误:

Caused by: org.hibernate.QueryException: could not resolve property: name of: (....).model.employee.Employee

所以问题是:如何告诉spring去寻找 name 在关联字段中?如何处理spring数据?
我已经试过几种方法,但都不起作用,或者我仍然不知道如何正确使用它们:
有人建议添加 countQuery@Query 参数,因此这在某种程度上与分页(spring data jpa@query和pageable)相对应
我遵循了baeldung的教程,但这不包括连接
带分页的spring数据获取连接不起作用也建议使用 countQuery 但我更愿意坚持 Page<Employee> 而不是 List<Employee> .
我将在下面留下一些代码示例。如果我遗漏了一些重要的事情,请随时要求更新。

// Employee
@Entity
@Table(name = "employee", schema = "emp")
@Data
@NoArgsConstructor
public class Employee {
    private static final String SEQUENCE = "EMPLOYEE_SEQUENCE";

    @Id
    @SequenceGenerator(sequenceName = SEQUENCE, name = SEQUENCE, allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = SEQUENCE)
    private Long id;

    @Column(name = "employee_number")
    private String employeeNumber;

    @Column
    @Enumerated(EnumType.STRING)
    private EmployeeStatus status;

    @OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @Audited(targetAuditMode = RelationTargetAuditMode.NOT_AUDITED)
    @JoinColumn(name = "id_details")
    private Details details;

    // some other fields ...
}
// Details
@Entity
@Table(name = "details", schema = "emp")
@Data
@NoArgsConstructor
public class Details {
    private static final String SEQUENCE = "DETAILS_SEQUENCE";

    @Id
    @SequenceGenerator(sequenceName = SEQUENCE, name = SEQUENCE, allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = SEQUENCE)
    private Long id;

    private String name;

    private String surname;

    // some other fields ...
}
// EmployeeDTO
@NoArgsConstructor
@AllArgsConstructor
@Data
@Builder(toBuilder = true)
public class EmployeeDTO {
    private Long id;
    private String employeeNumber;
    private String status;
    private String name;
    private String surname;

    // some other fields ...
}
// EmployeeRepository
@Repository
public interface EmployeeRepository extends JpaRepository<Employee, Long> {

    // 1st method
    Page<Employee> findByStatus(EmployeeStatus status, Pageable pageable);

    // 2nd method
    @Query(value = "select e from Employee e join e.details where e.status = :status",
            countQuery = "select count(*) from Employee e join e.details where e.status = :status")
    Page<Employee> getEmployeeDetails(@Param("status") EmployeeStatus status, Pageable pageable);

    // 3rd method
    @Query("select e from Employee e join fetch e.details where e.id = :id")
    Optional<Employee> findByIdWithDetails(Long id);

    // ...
}
// EmployeeService
@Service
public class EmployeeService {

    private final EmployeeRepository employeeRepository;
    private final EntityDtoConverter entityDtoConverter;

    @Autowired
    public EmployeeService(EmployeeRepository employeeRepository, EntityDtoConverter entityDtoConverter) {
        this.employeeRepository = employeeRepository;
        this.entityDtoConverter = entityDtoConverter;
    }

    public EmployeeResponse getEmployeesByStatus(EmployeeStatus status, int pageSize, int pageIndex, Sort.Direction sortDirection, String sortColumn) {
        Page<EmployeeDTO> employeePage = employeeRepository.findByStatus(status, PageRequest.of(pageIndex, pageSize, Sort.by(sortDirection, sortColumn)))
                .map(entityDtoConverter::convertEmployeeBaseToDto);
        return new EmployeeResponse(employeePage);
    }

    public EmployeeResponse getEmployeeDetails(EmployeeStatus status, int pageSize, int pageIndex, Sort.Direction sortDirection, String sortColumn) {
        Page<EmployeeDTO> employeePage = employeeRepository.getEmployeeDetails(status, PageRequest.of(pageIndex, pageSize, Sort.by(sortDirection, sortColumn)))
                .map(entityDtoConverter::convertToEmployeeWithDetailsDto);
        return new EmployeeResponse(employeePage);
    }

    // ...
}
// EntityDtoConverter
@Component
public class EntityDtoConverter {

    public EmployeeDTO convertEmployeeBaseToDto(Employee entity) {
        return EmployeeDTO.builder()
                .id(entity.getId())
                .employeeNumber(entity.getEmployeeNumber())
                .status(entity.getStatus())
                .build();
    }

    public EmployeeDTO convertToEmployeeWithDetailsDto(Employee entity) {
        return convertEmployeeBaseToDto(entity).toBuilder()
                .name(entity.getDetails().getName())
                .surname(entity.getDetails().getSurname())
                .build();
    }

    // ...
}

编辑:

这是我的rest控制器的方法之一:

@GetMapping
public ResponseEntity<EmployeeResponse> getEmployeesByStatus(EmployeeStatus status, int pageSize, int pageIndex, String sortDirection, String sortColumn) {
    try {
        EmployeeResponse employeeResponse = employeeService.getEmployeesByStatus(status, pageSize, pageIndex, Sort.Direction.fromString(sortDirection), sortColumn);
        return employeeResponse.getTotalElements().equals(0L) ? ResponseEntity.noContent().build() : ResponseEntity.ok(employeeResponse);
    } catch (Exception e) {
        log.error(ERROR_MESSAGE, e);
        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
    }
}
ifmq2ha2

ifmq2ha21#

试试下面的代码。

Specification<Employee> joins = (employee, query, cb) ->  {
            Join<Employee, Detail> details = employee.join("details");

            return cb.and(
                    employee.equal(employee.get("name", name)),
                    details.equal(details.get("name", detailName))
            );
        };

        PageRequest pageRequest = new PageRequest(0, 2, new Sort(Sort.Direction.DESC, "name"));

        Page<Employee> customerPage = employeeRepository.findAll(joins, pageRequest);

这里我们试图通知jpa这个名称是employee表的外键。

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