[Spring] File 을 MultipartFile 로 변경

https://stackoverflow.com/questions/16648549/converting-file-to-multipartfile

스택오버 플로우에서 file 을 MultipartFile 로 변경하는 방법을 소개했다.

 

import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import org.springframework.mock.web.MockMultipartFile;

Path path = Paths.get("/path/to/the/file.txt");
String name = "file.txt";
String originalFileName = "file.txt";
String contentType = "text/plain";
byte[] content = null;
try {
    content = Files.readAllBytes(path);
} catch (final IOException e) {
}
MultipartFile result = new MockMultipartFile(name,
                     originalFileName, contentType, content);

 

 

MockMultipartFile 을 사용하여 파일을 생성, Controller 로 넘김.

// dto 에선 multipartFile 을 받는다.
public static class Test {
	private MultipartFile file;
}

dto 에서 변환 과정에서 오류 발생.

org.springframework.http.converter.HttpMessageConversionException: Type definition error: [simple type, class java.io.ByteArrayInputStream]; nested exception is com.fasterxml.jackson.databind.exc.InvalidDefinitionException: 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: com.vehicle.web.rest.dto.TestDTO$PostDto["file"]->org.springframework.mock.web.MockMultipartFile["inputStream"])

 

 

해결

    @PostMapping
    public ResponseEntity<Long> create(@Valid @RequestPart(value = "dto") UserDTO.PostDto request, BindingResult bindingResult,
                                       @RequestPart(value = "file") MultipartFile file,
                                       @RequestParam("userId") String userId) throws URISyntaxException, IOException, ExecutionException, InterruptedException {
        if (bindingResult.hasErrors()) {
            throw new BadRequestAlertException("A required value is missing.", ENTITY_NAME, HttpStatus.BAD_REQUEST.toString());
        }
        UserDTO.PostDto response = userMapper.toDto(userService.create(userMapper.toEntity(request), file, userId));
        return ResponseEntity.created(new URI("/api/user/" + response.getUserId()))
                .headers(HeaderUtil.createEntityCreationAlert(applicationName, true, ENTITY_NAME,
                        response.getUserId().toString()))
                .body(response.getUserId());
    }

HttpHeaders httpHeaders = new HttpHeaders();
httpHeaders.setContentType(MediaType.MULTIPART_FORM_DATA);
MultiValueMap<String, Object> map = new LinkedMultiValueMap<>();
Resource resource = new FileSystemResource(file.toPath());
map.add("file", resource);
map.add("dto", dto);
HttpEntity<MultiValueMap<String, Object>> requestEntity = new HttpEntity<>(map, httpHeaders);

• 테스트 코드에선 header 설정 과 Resource, map 을 사용하며, RestTemplate 를 사용해서 넘겨줬음.
• 위 file 로 넘겨준 객체가 정상적으로 매핑되는걸 확인.