code: public String getMimeType() {
  		FileItemWrap fileItem = getFile();
  		if (fileItem != null) {
  			return FileUtil.getFileMimeType(fileItem);
  		}
  		return null;
  	}
docs: Retrieves an mime type of the uploaded file's contents.
  This is not the content type passed by the browser.
  
  @return an file's mime type, or null if no file has been uploaded