获取子网络地址范围

/**
来 自 时   代    Java - nowjava.com
**/


//package com.nowjava;


public class Main {

    /**

     * 

     * @param hostAddress

     *            ,ex: 192.168.1.222

     * @param networkPrefixLength

     *            ,ex: 24

     * @return

     */

    public static byte[][] getSubNetworkAddressRange(String hostAddress,

            short networkPrefixLength) {

        byte[] addressBytes = getBytesOfHostAddress(hostAddress);


        byte[][] addressRange = new byte[2][];

        addressRange[0] = new byte[addressBytes.length];

        addressRange[1] = new byte[addressBytes.length];


        final int addressBitLength = addressBytes.length * 8;


        for (int i = 0; i < addressBytes.length; i++) {

            if ((i + 1) * 8 + networkPrefixLength <= addressBitLength) {/*n o w j a v a . c o m - 时  代  Java 提 供*/

                // host

                addressRange[0][i] = 0;

                addressRange[1][i] = (byte) 0xff;

            } else if (i * 8 + networkPrefixLength < addressBitLength) {

                // host and network

                addressRange[0][i] = addressRange[1][i] = addressBytes[i];


                byte bits = (byte) 0xff;

                int moveBitCount = 8 - networkPrefixLength % 8;

                bits = (byte) (bits >>> moveBitCount << moveBitCount);


                addressRange[0][i] &= bits;

                addressRange[1][i] |= (~bits);

            } else {

                // network

                addressRange[0][i] = addressRange[1][i] = addressBytes[i];

            }

        }


        if (addressRange[0][0] == 0) {

            addressRange[0][0] = 1;

        }

        if (addressRange[1][0] == (byte) 0xff) {

            addressRange[1][0]--;

        }


        return addressRange;

    }


    /**

     * 

     * @param hostAddress

     *            ex:192.168.1.222

     * @return

     */

    public static byte[] getBytesOfHostAddress(String hostAddress) {

        String[] hostAddressParts = hostAddress.split("\\.");


        byte[] bytes = new byte[hostAddressParts.length];

        for (int i = 0; i < hostAddressParts.