code: public static boolean writeStream(String filePath, InputStream stream, boolean append) throws IOException {
          return writeStream(filePath != null ? new File(filePath) : null, stream, append);
      }
docs: write file
  
  @param filePath the file to be opened for writing.
  @param stream   the input stream
  @param append   if <code>true</code>, then bytes will be written to the end of the file rather than the beginning
  @return return true
  @throws IOException if an error occurs while operator FileOutputStream