java - 无法使用 Spring Boot 测试测试 MockMultipartFile - 找不到序列化器

Question

我正在尝试模拟将图像上传到 Controller 端点，该端点需要包含 MultipartFile 输入以及多个纯文本字段的 DTO。但我似乎无法模拟要发送的 MultipartFile:

这是我的测试:

 @Test
  public void saveAnEntryWhenPOSTNewUserWithAPicture() throws Exception {
    MockMultipartFile multiPFImage = new MockMultipartFile("contactImgUpload", "abcpic.png",
            "text/plain", "Generate bytes to simulate a picture".getBytes());
    mockMvc.perform(MockMvcRequestBuilders.fileUpload("/newContact")
            .file(multiPFImage)
            .contentType(MediaType.MULTIPART_FORM_DATA)
            .param("userId", "12345")
            .param("name", "Picture Uploader User"))
            .andExpect(status().isOk())
            .andExpect(content().string(containsString("Picture Uploader User")))
            .andExpect(content().string(containsString("Replace with image title")));
  }

我们正在测试的 Controller 方法:

@PostMapping(path = "/newContact")
  public @ResponseBody ContactDTO createNewContact(@ModelAttribute ContactDTO newContact) {

   //converts newContact to DAO and persists to DB

   return newContact
}

用于转换的DTO:

public class ContactDTO implements Serializable {

  private BigInteger userId;
  private BigInteger contactId; //automatically generated on persistence
  private String name;
  private MultipartFile contactImgUpload;
}

当我运行测试时，它失败了，并且我收到以下消息:

.w.s.m.s.DefaultHandlerExceptionResolver : Failed to write HTTP message: org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: No serializer found for class java.io.ByteArrayInputStream and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS); nested exception is com.fasterxml.jackson.databind.JsonMappingException: No serializer found for class java.io.ByteArrayInputStream and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: app.models.dto.ContactDTO["contactImgUpload"]->org.springframework.mock.web.MockMultipartFile["inputStream"])

我见过这个问题的其他几个实例，但大多数都没有答案，或者并不完全相同。关于如何测试需要绑定(bind)到 DTO 的 MockMultipartFile 有什么想法吗？

Answer 1

你可以使用这个:

@Autowired
private ObjectMapper mapper;

@Before
public void before() {
    mapper.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS);
}