get Sub Network Address Range - Java Network

Java examples for Network:Network Address

  1. HOME
  2. Java
  3. Network
  4. Network Address

Description

get Sub Network Address Range

Demo Code


//package com.java2s;

public class Main {
    /**//w w  w .  jav a 2 s  .com
     * 
     * @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) {
                // 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.length; i++) {
            bytes[i] = (byte) Short.parseShort(hostAddressParts[i]);
        }

        final int halfBytesLength = bytes.length / 2;
        for (int i = 0; i < halfBytesLength; i++) {
            final byte b = bytes[i];
            bytes[i] = bytes[bytes.length - 1 - i];
            bytes[bytes.length - 1 - i] = b;
        }
        return bytes;
    }
}

Related Tutorials