我正在开发一个 spring boot 应用程序。 服务方法使用在服务中 Autowiring 的 GridFsTemplate 将 PDF 上传到 mongodb 存储库。 此文件上传服务方法通过 postman 休息客户端按预期工作。 但是，当我尝试运行单元测试时；调用相同的服务方法，SpringData GridFsTemplate 未初始化(在 MongoDB 中，您可以使用 GridFS 存储二进制文件)。这导致 org.springframework.data.mongodb.gridfs.GridFsTemplate.store(...) 抛出 NullPointerException。 拜托，你能帮忙吗，我已经被困在这几天了。

下面是我的服务实现:

@Service
public final class UploadServiceImpl implements UploadService {

    @Autowired
    private SequenceRepository sequenceDao;

    @Autowired (required = true)
    private GridFsTemplate gridFsTemplate;

    @Override
    public Long uploadFile(Invoice uploadedInvoice) {

        ByteArrayInputStream byteArrayInputStream = null;

        if (checkContentType(invoiceInfo.getContentType())) {

            invoiceInfo.setPaymentID(sequenceDao.getNextSequenceId(INVOICE_UPLOAD_SEQ_KEY));
            byteArrayInputStream = new ByteArrayInputStream(uploadedInvoice.getFileContent());

//Error thrown is java.lang.NullPointerException: null, where     gridFsTemplate is null and basically autowire does not work when test is     run.

                GridFSFile gridFSUploadedFile=     gridFsTemplate.store(byteArrayInputStream, invoiceInfo.getFileName(),     invoiceInfo.getContentType(), invoiceInfo);
                return  1l;

        } else {
            return 2l;
        }
    }

@RunWith(MockitoJUnitRunner.class)
@ContextConfiguration
public class UploadServiceTest {

    @Mock
    private SequenceRepository sequenceRepositoryMock;

    @Autowired
    private GridFsTemplate gridFsTemplateMock;

    @Mock
    private Invoice invoiceMock;

    @InjectMocks
    private static UploadService uploadService = new UploadServiceImpl();

    DBObject fileMetaData = null;

    DB db = null;
    Jongo jongo = null;

 @Before
    public void setUp() throws Exception {
        db = new Fongo("Test").getDB("Database");
        jongo = new Jongo(db);
    }

@Test
    public void testUploadFile() {

        //test 1
        Long mockPaymentNo = new Long(1);
        Mockito.when(sequenceRepositoryMock.getNextSequenceId(INVOICE_SEQUENCE)).thenReturn(mockPaymentNo);
        assertEquals(mockPaymentNo, (Long) sequenceRepositoryMock.getNextSequenceId(INVOICE_SEQUENCE));

        //test 2

        Invoice dummyInvoice = getDummyInvoice();
        InvoiceInfo dummyInvoiceInfo = dummyInvoice.getInvoiceInfo();

        MongoCollection invoicesCollection = jongo.getCollection("invoices");

        assertNotNull(invoicesCollection.save(dummyInvoiceInfo));
        assertEquals(1, invoicesCollection.save(dummyInvoiceInfo).getN());

        System.out.println("TEST 2 >>>>>>>>>>>>>>>>>> "+ uploadService);


        //test 3 : The following line is the cause of the exception, the service method is called but the GridFsTemplate is not initialized when the test is run. But it works when the endpoint is invoked via postman

        uploadService.uploadFile(dummyInvoice);

        System.out.println("TEST 3 >>>>>>>>>>>>>>>>>> ");

    }
}

最佳答案

问题是因为您使用@InjectMocks 来 Autowiring 您的UploadService。 并且 UploadService Autowiring 另外两个 bean SequenceRepository 和 GridFsTemplate。

If you’re doing TDD or not (and we are able to change the test first) – clients of this code don’t know about an additional dependency, because it’s completely hidden

Javadoc 声明:

Mockito will try to inject mocks only either by constructor injection, setter injection, or property injection in order and as described below. If any of the following strategy fail, then Mockito won’t report failure; i.e. you will have to provide dependencies yourself.

解决方案是使用 UploadServiceImpl 构造函数来 Autowiring bean:

@Service
public final class UploadServiceImpl implements UploadService {

    private final SequenceRepository sequenceDao;
    private final GridFsTemplate gridFsTemplate;
    private final PlannerClient plannerClient;

    @Autowired
    public PlannerServiceImpl(PlannerClient plannerClient, GridFsTemplate gridFsTemplate, SequenceRepository sequenceDao) {
        this.plannerClient = plannerClient;
    }
...

}

当需要更多的依赖时，它们是清晰可见的，因为它们是在构造函数中初始化的

更详细:

https://tedvinke.wordpress.com/2014/02/13/mockito-why-you-should-not-use-injectmocks-annotation-to-autowire-fields/

关于spring - 服务单元测试类中的 GridFsTemplate NullPointerException(技术堆栈 : Spring Data/Spring Boot/Micro Service/Mongodb )，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/38014699/