code: public void send() throws IOException {
  
          HashMap<String, RequestData.UploadFileInfo> uploadFiles = mRequestData.getUploadFiles();
  
          HashMap<String, Object> mPostData = mRequestData.getPostData();
          // send data to Server
          if (mPostData != null && mPostData.size() != 0) {
  
              Iterator<Map.Entry<String, Object>> iterator = mPostData.entrySet().iterator();
              while (iterator.hasNext()) {
                  Map.Entry<String, Object> item = iterator.next();
                  Object value = item.getValue();
                  if (value == null) {
                      value = "";
                  }
                  addFormField(item.getKey(), value.toString());
              }
          }
  
          // send file to server
          Iterator<Map.Entry<String, RequestData.UploadFileInfo>> iterator = uploadFiles.entrySet().iterator();
          while (iterator.hasNext()) {
              Map.Entry<String, RequestData.UploadFileInfo> item = iterator.next();
              RequestData.UploadFileInfo uploadFileInfo = item.getValue();
              addFilePart(uploadFileInfo.fieldName, uploadFileInfo.uploadFile, uploadFileInfo.fileName);
          }
      }
docs: post data to Server