code: private String getFileName(String contentDisposition) {
  		String fileName = null;
  
  		if (contentDisposition != null) {
  			String cdl = contentDisposition.toLowerCase();
  
  			if (cdl.startsWith(FORM_DATA) || cdl.startsWith(ATTACHMENT)) {
  
  				ParameterParser parser = new ParameterParser();
  				parser.setLowerCaseNames(true);
  
  				// parameter parser can handle null input
  				Map<String,String> params = parser.parse(contentDisposition, ';');
  				if (params.containsKey("filename")) {
  					fileName = (String) params.get("filename");
  					if (fileName != null) {
  						fileName = fileName.trim();
  					} else {
  						// even if there is no value, the parameter is present,
  						// so we return an empty file name rather than no file
  						// name.
  						fileName = "";
  					}
  				}
  			}
  		}
  
  		return fileName;
  	}
docs: Retrieves the file name of a file from the filename attribute of the Content-Disposition header of the part.
  
  @param contentDisposition the value of the Content-Disposition header.
  
  @return a String object that holds the name of the file.