关于Java：无法使用Spring Boot Test测试MockMultipartFile-未找到序列化程序


Cannot Test MockMultipartFile with Spring Boot Test - No serializer found

我正在尝试模拟将图像上传到控制器端点，该控制器期望DTO包含MultipartFile输入以及几个纯文本字段。但我似乎无法模拟要发送的MultipartFile：

这是我的考试：

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 @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")));
  }

我们正在测试的控制器方法：

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

   //converts newContact to DAO and persists to DB

   return newContact
}

要转换的DTO：

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public class ContactDTO implements Serializable {

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

运行测试时，它失败，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"])

我已经看到过这个问题的其他几个实例，但是大多数都没有答案，或者答案不尽相同。关于如何测试需要绑定到DTO的MockMultipartFile的任何想法？

您可以使用此：

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@Autowired
private ObjectMapper mapper;

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