java--正则表达式使用

private String parseIp(String jdbc) {
        String pattern = "((25[0-5]|2[0-4]\\d|((1\\d{2})|([1-9]?\\d)))\\.){3}(25[0-5]|2[0-4]\\d|((1\\d{2})|([1-9]?\\d)))";
        Pattern r = Pattern.compile(pattern);
        Matcher m = r.matcher(jdbc);
        if (m.find()) {
            return m.group();
        }
        return "";
    }