Java tutorial
//package com.java2s; import java.net.InetAddress; public class Main { /** * Checks validity of a dotted IP address string. * Uses {@link java.net.InetAddress}.getByName() method. * * @param ipStr * @return */ public static boolean isValidIp(String ipStr) { try { InetAddress ip = InetAddress.getByName(ipStr); return ip2Long(ipStr) > 0; } catch (Exception e) { return false; } } /** * Transforms dotted IP address to long number. * * @param ipStr Dotted ip ie. "127.0.0.1" * @return Long number ie. "2130706433" */ public static long ip2Long(String ipStr) { long result = 0; try { InetAddress ip = InetAddress.getByName(ipStr); byte[] octets = ip.getAddress(); for (byte octet : octets) { result <<= 8; result |= octet & 0xff; } } catch (Exception e) { } return result; } }