Spring RestTemplate POST upload multiple files

Question

Let's assume I have an endpoint looking like the one below:

  @PostMapping(
      value = "/something",
      consumes = MULTIPART_FORM_DATA_VALUE,
      produces = APPLICATION_JSON_VALUE)
  public SomeDTO post2Files(
      @RequestPart("file1") MultipartFile file1,
      @RequestPart("file2") MultipartFile file2 {

In another service I want to read one file from the file system and just resend it, while the file2 is actually a string that I wanna pass as a file through RestTemplate. I tried something like this:

   HttpHeaders headers = new HttpHeaders();
   headers.setContentType(MediaType.MULTIPART_FORM_DATA);
   MultiValueMap<String, Object> body = new LinkedMultiValueMap<>();
   body.add("file1", new FileSystemResource(somePath));
   body.add("file2", new ByteArrayResource(someString.getBytes()));
   restTemplate.postForObject("/something", new HttpEntity<>(body, headers), SomeDTO.class)

It doesn't work and I have no clue why. I get 400. What should I do to make the request pass through?

Answer 1

Figured it out. This is the solution:

body.add("dataSchema", new ByteArrayResource(someString.getBytes()) {
            @Override
            public String getFilename() {
                return "file2";
            }
        });

It didn't work because the filename did not match with the @RequestPart.