CODE EXAMPLE FOR JAVA

java regex ip

public static boolean isIP(String ip)  {
    Pattern p = Pattern.compile("(([01]?[0-9]{1,2}|2[0-4][0-9]|25[0-5]).){3}([01]?[0-9]{1,2}|2[0-4][0-9]|25[0-5])");
    Matcher m = p.matcher(ip);
    return m.matches();
}