C#使用正则判断一个字符串是否为IP地址:
private boolean isIp(String ip) {
String rex =
"^([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\." +
"([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\." +
"([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\." +
"([01]?\\d\\d?|2[0-4]\\d|25[0-5])$";
Pattern pattern = Pattern.compile(rex);
Matcher matcher = pattern.matcher(ip);
return matcher.find();
}