将Java对象转换为JSON对象时出错

Question

Using jackson API, I am trying to convert java object to json string. I have gone through several posts but not able to through the below stack-trace.

com.fasterxml.jackson.databind.JsonMappingException: No serializer found for class java.io.FileDescriptor and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: com.imc.idm.data.request.DirectoryDetailData["logoImage"]->org.springframework.web.multipart.support.StandardMultipartHttpServletRequest$StandardMultipartFile["inputStream"]->java.io.FileInputStream["fd"])
    at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:284)
    at com.fasterxml.jackson.databind.SerializerProvider.mappingException(SerializerProvider.java:1110)
    at com.fasterxml.jackson.databind.SerializerProvider.reportMappingProblem(SerializerProvider.java:1135)
    at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.failForEmpty(UnknownSerializer.java:69)

My code is similar to this one below:

public class Infomation {
    private MultipartFile img;
    private Manufacture manufacture;
    private List<Long> otherVal1;
    private List<MyCustomClass> otherVal2;
}

Component :

ObjectMapper objectMapper = new ObjectMapper();
final String jsonString = objectMapper.writeValueAsString(infomationObject);
final MyDTO myDto = MyDTO.newBuilder().withValue(jsonString).build();
dataRepository.save(myDto);

Answer 1

Serializable interface/marker is not implemented in MultipartFile .

If you have Spring Web in your dependencies, you can use CommonsMultipartFile as it implements Serializable and MultipartFile.

For more information, please see Commons Multipart File Java API