Java – Multipart File upload Spring Boot

javamultipartspringspring-bootspring-mvc

Im using Spring Boot and want to use a Controller to receive a multipart file upload.
When sending the file I keep getting the error 415 unsupported content type response and the controller is never reached

There was an unexpected error (type=Unsupported Media Type, status=415).
Content type 'multipart/form-data;boundary=----WebKitFormBoundary1KvzQ1rt2V1BBbb8' not supported

Ive tried sending using form:action in html/jsp page and also in a standalone client application which uses RestTemplate. All attempts give the same result

multipart/form-data;boundary=XXXXX not supported.

It seems from multipart documentation that the boundary param has to be added to the multipart upload however this seems to not match the controller receiving "multipart/form-data"

My controller method is setup as follows 

@RequestMapping(value = "/things", method = RequestMethod.POST, consumes = "multipart/form-data" ,
                                     produces = { "application/json", "application/xml" })
     public ResponseEntity<ThingRepresentation> submitThing(HttpServletRequest request,
                                     @PathVariable("domain") String domainParam,
                                     @RequestParam(value = "type") String thingTypeParam,
                                     @RequestBody MultipartFile[] submissions) throws Exception

With Bean Setup

 @Bean
 public MultipartConfigElement multipartConfigElement() {
     return new MultipartConfigElement("");
 }

 @Bean
 public MultipartResolver multipartResolver() {
     org.springframework.web.multipart.commons.CommonsMultipartResolver multipartResolver = new org.springframework.web.multipart.commons.CommonsMultipartResolver();
     multipartResolver.setMaxUploadSize(1000000);
     return multipartResolver;
 }

As you can see I've set the consumes type to "multipart/form-data" but when the multipart is sent it must have a boundary parameter and places a random boundary string.

Can anyone please tell me how I can either set the content type in controller to match or change my request to match my controller setup?

My attempts to send …
Attempt 1…

<html lang="en">
<body>

    <br>
    <h2>Upload New File to this Bucket</h2>
    <form action="http://localhost:8280/appname/domains/abc/things?type=abcdef00-1111-4b38-8026-315b13dc8706" method="post" enctype="multipart/form-data">
        <table width="60%" border="1" cellspacing="0">
            <tr>
                <td width="35%"><strong>File to upload</strong></td>
                <td width="65%"><input type="file" name="file" /></td>
            </tr>
            <tr>
                <td>&nbsp;</td>
                <td><input type="submit" name="submit" value="Add" /></td>
            </tr>
        </table>
    </form>
</body>
</html>

Attempt 2….

RestTemplate template = new RestTemplate();
MultiValueMap<String, Object> parts = new LinkedMultiValueMap<String, Object>();
parts.add("file", new FileSystemResource(pathToFile));

try{

    URI response = template.postForLocation(url, parts);
}catch(HttpClientErrorException e){
    System.out.println(e.getResponseBodyAsString());
}

Attempt 3…

FormHttpMessageConverter formHttpMessageConverter = new FormHttpMessageConverter();
        formHttpMessageConverter.setCharset(Charset.forName("UTF8"));


        RestTemplate restTemplate = new RestTemplate();

        restTemplate.getMessageConverters().add( formHttpMessageConverter );
        restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
        restTemplate.setRequestFactory(new HttpComponentsClientHttpRequestFactory());

        MultiValueMap<String, Object> map = new LinkedMultiValueMap<String, Object>();
        map.add("file", new FileSystemResource(path));

        HttpHeaders imageHeaders = new HttpHeaders();
        imageHeaders.setContentType(MediaType.MULTIPART_FORM_DATA);

        HttpEntity<MultiValueMap<String, Object>> imageEntity = new HttpEntity<MultiValueMap<String, Object>>(map, imageHeaders);
        ResponseEntity e=  restTemplate.exchange(uri, HttpMethod.POST, imageEntity, Boolean.class);
        System.out.println(e.toString());

Best Answer

@RequestBody MultipartFile[] submissions

should be 

@RequestParam("file") MultipartFile[] submissions

The files are not the request body, they are part of it and there is no built-in HttpMessageConverter that can convert the request to an array of MultiPartFile.

You can also replace HttpServletRequest with MultipartHttpServletRequest, which gives you access to the headers of the individual parts.

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