Question

今天，我的私人项目有问题。虽然实体每次接收NullPointerException都会节省DTO的使用量。

通常，直到现在，我一直在使用不带ID标识符的DTO，但最后却发现我需要一个ID字段，因为在GUI端需要它来修改或删除一个特定的对象。

以下具有DTO的实体：

@RequiredArgsConstructor
public class DiscountCode {
  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long id;

  @NonNull private LocalDateTime startDate;
  @NonNull private LocalDateTime endDate;

  @NonNull @NotBlank private String code;

  private Integer quantity;
  @NonNull private BigDecimal rate;

  @NonNull
  @Enumerated(EnumType.STRING)
  private DiscountCodeStatus status;
}

@RequiredArgsConstructor
public class DiscountCodeDto {

  private Long id;

  @NonNull private LocalDateTime startDate;
  @NonNull private LocalDateTime endDate;
  @NonNull private String code;

  private Integer quantity;

  @NonNull private BigDecimal rate;

  @NonNull
  @Enumerated(EnumType.STRING)
  private DiscountCodeStatus status;
}

具有完整的lombok实用程序。

下面的映射器：

public class DiscountCodeMapper {

  private DiscountCodeMapper() {
    throw new UnsupportedOperationException();
  }

  public static DiscountCodeDto toDto(DiscountCode discountCode) {
    return isNull(discountCode)
        ? null
        : DiscountCodeDto.builder()
            .id(discountCode.getId())
            .startDate(discountCode.getStartDate())
            .endDate(discountCode.getEndDate())
            .code(discountCode.getCode())
            .quantity(discountCode.getQuantity())
            .rate(discountCode.getRate())
            .build();
  }

  public static DiscountCode fromDto(DiscountCodeDto discountCodeDto) {
    return isNull(discountCodeDto)
        ? null
        : DiscountCode.builder()
            .id(discountCodeDto.getId())
            .startDate(discountCodeDto.getStartDate())
            .endDate(discountCodeDto.getEndDate())
            .code(discountCodeDto.getCode())
            .quantity(discountCodeDto.getQuantity())
            .rate(discountCodeDto.getRate())
            .build();
  }
}

以下服务方法：

@Service
@RequiredArgsConstructor
public class DiscountCodeService {

  private final DiscountCodeRepository discountCodeRepository;

  public DiscountCodeDto add(final DiscountCodeDto discountCodeDto) {
    checkArgument(nonNull(discountCodeDto), "Expected not null discountCodeDto");

    DiscountCode discountCode =
        discountCodeRepository.save(Objects.requireNonNull(fromDto(discountCodeDto)));

    return DiscountCodeDto.builder()
        .id(discountCode.getId())
        .startDate(discountCode.getStartDate())
        .endDate(discountCode.getEndDate())
        .code(discountCode.getCode())
        .quantity(discountCode.getQuantity())
        .rate(discountCode.getRate())
        .status(discountCode.getStatus())
        .build();
  }

JUnit 5，带有测试用例：

class DiscountCodeTest {

  private DiscountCodeService discountCodeService;
  private DiscountCodeRepository discountCodeRepository = mock(DiscountCodeRepository.class);

  @BeforeEach
  void setUp() {
    discountCodeService = new DiscountCodeService(discountCodeRepository);
  }

  @AfterEach
  void tearDown() {
    reset(discountCodeRepository);
  }

  @Test
  void shouldAddDiscountCode() {
    // given
    Long expectedDiscountCodeId = 1L;
    DiscountCode expectedDiscountCode =
        new DiscountCode(
            expectedDiscountCodeId,
            LocalDateTime.now().plusDays(1),
            LocalDateTime.now().plusDays(5),
            "7142",
            null,
            BigDecimal.valueOf(100),
            DiscountCodeStatus.ACTIVE);

    DiscountCodeDto givenDiscountCodeDto =
        new DiscountCodeDto(
            LocalDateTime.now().plusDays(1),
            LocalDateTime.now().plusDays(5),
            "7142",
            BigDecimal.valueOf(100),
            DiscountCodeStatus.ACTIVE);

    when(discountCodeRepository.save(any())).thenReturn(expectedDiscountCode);
    // when
    DiscountCodeDto actualDiscountCode = discountCodeService.add(givenDiscountCodeDto);
    // then
    verify(discountCodeRepository).save(any(DiscountCode.class));
    assertEquals(givenDiscountCodeDto, actualDiscountCode);
  }

当前，在每种情况下，我都会收到该行的NullPointerException：

DiscountCodeDto实际DiscountCode = discountCodeService.add（givenDiscountCodeDto）;

在测试案例部分中

。我要做的就是在不使用ID到DTO对象的情况下保存使用DTO的实体。

我试图用邮递员用法执行add方法，但是在这种情况下，我都收到NullPointerException。

在此先感谢您的帮助。

NullPointerException，而实体使用dto进行保存

0 个答案: