Here are the core libraries I used.
Apache Commons FileUpload 1.2.1
Apache HttpClient 4.2.1 (which includes httpmime-4.1.2.jar)
Creating a multipart post request:
public void postMultipartMessage() throws ClientProtocolException, IOException
{
HttpPost postRequest = new HttpPost("http://host:port/webapp/servlet");
MultipartEntity reqEntity = new MultipartEntity();
//Add a string parameter StringBody strBody = new StringBody("string parameter");
reqEntity.addPart("string", strBody);
//Add a file attachment FileBody fileBody = new FileBody(new File("/file/path"));
reqEntity.addPart("file", fileBody);
postRequest.setEntity(reqEntity);
HttpContext httpContext = new BasicHttpContext();
HttpResponse response = getHttpClient().execute(postRequest, httpContext); //getHttpClient() initializes the http client object perhaps from a properties file
}This could also have been done by submitting a multipart http request using a jsp presented to a user but the idea here is to show how this can be done programatically between two servers with no end user involved.
Processing a multipart post request on the server side:
public void processMultipartMessage(HttpServletRequest request) throws FileUploadException, IOException
{
if(request.getMethod().equals(URIConstants.HTTP_METHOD.POST.toString()))
{
if(request.getContentType().toUpperCase().contains("MULTIPART"))
{
List<FileItem> items = new ServletFileUpload(new DiskFileItemFactory()).parseRequest(request);
for (FileItem item : items)
{
if (item.isFormField())
{
// Retrieve form field
String fieldname = item.getFieldName();
String fieldvalue = item.getString();
// do whatever needs to be done with form field..
}
else
{
// Process form file field (input type="file").
String filename = FilenameUtils.getName(item.getName());
InputStream filecontent = item.getInputStream();
// do whatever needs to be done with form file field..
}
}
}
}
}
