Spring Resttemplate : how to post file and common String data at the same time

Question

I meet a request to upload files with spring resttemplate to upload files with http header "multipart/form-data", also some other normal parameters need to be posted. how to implements that?

Answer 1

you can use the following code in your application to have both multipartfile and normal request parameters at the same time.

• Replace the url with your own.

• replace param and value according to your normal parameters.

  String url ="http://example.com"; String fileAbsPath ="absolute path of your file"; String fileName = new File(fileAbsPath).getName(); Files.readAllBytes(Paths.get(fileAbsPath)); MultiValueMap<String, Object> data = new LinkedMultiValueMap<String, Object>(); ByteArrayResource resource = new ByteArrayResource(Files.readAllBytes(Paths.get(fileAbsPath))) { @Override public String getFilename() { return fileName; } }; data.add("file", resource); HttpHeaders requestHeaders = new HttpHeaders(); requestHeaders.set("file","application/pdf"); UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl(url) .queryParam("param1", "value1") .queryParam("param2", "value2") HttpEntity<> entity = new HttpEntity<> (data, requestHeaders); RestTemplate restTemplate = new RestTemplate(); ResponseEntity<String> result =restTemplate.exchange( builder.toUriString(), HttpMethod.POST, entity, String.class); System.out.println(result.getBody());

Answer 2

you can use this code.

   HttpHeaders headers = getCASHeaders(MediaType.MULTIPART_FORM_DATA);
   LinkedMultiValueMap<String, Object> params = new LinkedMultiValueMap<>();
   params.add("fileField", new FileSystemResource(""));//get file resource
   params.add("stringfield", stringPayload);
   HttpEntity requestEntity = new HttpEntity<>(params, headers);
   ResponseEntity<CasAssetApiResponse> response = restTemplate.exchange(url, HttpMethod.POST, requestEntity, String.class);

This will send post call with two param, you can add more according to your wish.

Please have a look at this stackoverflow answer as well

Answer 3

I got the error "cannot be cast to java.lang.String" although my code does not have any casting.