public static long ip2num(String ip) {
    long ipNum = 0;
    try {
     if (ip != null) {
        String ips[] = ip.split("\\.");
        for (int i = 0; i < ips.length; i++) {
         int k = Integer.parseInt(ips[i]);
         ipNum = ipNum + k * (1L << ((3 - i) * 8));
        }
     }
    } catch (Exception e) {
    }
    return ipNum;
}

public static String num2ip(long longIp) {
    StringBuffer sb = new StringBuffer("");
    // 直接右移24位
    sb.append(String.valueOf((longIp >>> 24)));
    sb.append(".");
    // 将高8位置0，然后右移16位
    sb.append(String.valueOf((longIp & 0x00FFFFFF) >>> 16));
    sb.append(".");
    // 将高16位置0，然后右移8位
    sb.append(String.valueOf((longIp & 0x0000FFFF) >>> 8));
    sb.append(".");
    // 将高24位置0
    sb.append(String.valueOf((longIp & 0x000000FF)));
    return sb.toString();
}