Apache HttpClient making multipart POST to Spring #Controller class - spring

Question

It seems like there are several posts such as here asking how to use Apache Commons HTTPClient libraries in Java to do a POST to a Servlet. However, it seems like I'm having some problems doing the same thing with a annotated Spring controller method. I've tried a few things but gotten HTTP 401 Bad Request responses from the server. Any examples of doing this would be greatly appreciated.
EDIT: Code I am trying to use:
//Server Side (Java)
#RequestMapping(value = "/create", method = RequestMethod.POST)
public void createDocument(#RequestParam("userId") String userId,
#RequestParam("file") MultipartFile file, HttpServletResponse response) {
// Do some stuff
}
//Client Side (Groovy)
void processJob(InputStream stream, String remoteAddress) {
HttpClient httpclient = new DefaultHttpClient()
httpclient.getParams().setParameter(CoreProtocolPNames.PROTOCOL_VERSION, HttpVersion.HTTP_1_1)
HttpPost httppost = new HttpPost("http://someurl/rest/create")
MultipartEntity mpEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE)
InputStreamBody uploadFilePart = new InputStreamBody(stream, 'application/octet-stream', 'test.file')
mpEntity.addPart('file', uploadFilePart)
mpEntity.addPart('userId', new StringBody('testUser'))
httppost.setEntity(mpEntity)
HttpResponse response = httpclient.execute(httppost);
println(response.statusLine)
}
Still getting 400 Bad Request in the response from the server.

Answer 1

I hate to answer my own question when it shows incompetence, but it turns out the code was fine, this particular controller did not have a CommonsMultipartResolver defined in its servlet-context.xml file (multiple DispatcherServlets...long story :()
Here's what I added to make it work:
<!-- ========================= Resolver DEFINITIONS ========================= -->
<bean id="multipartResolver"
class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!-- one of the properties available; the maximum file size in bytes -->
<property name="maxUploadSize" value="50000000"/>
</bean>

Answer 2

Here is an example from the Spring Reference:
#Controller
public class FileUpoadController {
#RequestMapping(value = "/form", method = RequestMethod.POST)
public String handleFormUpload(#RequestParam("name") String name,
#RequestParam("file") MultipartFile file) {
if (!file.isEmpty()) {
byte[] bytes = file.getBytes();
// store the bytes somewhere
return "redirect:uploadSuccess";
} else {
return "redirect:uploadFailure";
}
}
}