docs: public static String toStr(Document doc, String charset, boolean isPretty) {
  		final StringWriter writer = StrUtil.getWriter();
  		try {
  			write(doc, writer, charset, isPretty ? INDENT_DEFAULT : 0);
  		} catch (Exception e) {
  			throw new UtilException(e, "Trans xml document to string error!");
  		}
  		return writer.toString();
  	}