JAVA IP地址用一個整形表示，IP地址和Int互轉

IP 地址分爲4個字段，每一個字段範圍是0－255，恰好用一個字段能夠表示，JAVA一個int是4個字節，每一個字節表示一個IP 段。

代碼：

 

public class TestIPInt extends TestCase {    public void testIPToInt() {        int ip1 = 1;        int ip2 = 1;        int ip3 = 1;        int ip4 = 2;        //1.1.1.2 ==16843010        //255.255.255.255 == -1        int ipint = ipToInt(ip1, ip2, ip3, ip4);        System.out.println("ipint:" + ipint);        int[] ipArr = intToIp(ipint);        for (int i = 0; i < 4; i++) {            System.out.print(ipArr[i] + ".");        }        System.out.println();    }    /**     * ip to int     * sample:192 168 1 2     *     * @param ip1     * @param ip2     * @param ip3     * @param ip4     * @return     */    public int ipToInt(int ip1, int ip2, int ip3, int ip4) {        return ipToInt(new int[]{ip1, ip2, ip3, ip4});    }    public int ipToInt(int[] ipArr) {        int ipInt = 0;        for (int i = 0; i < ipArr.length; i++) {            ipInt <<= 8;            ipInt ^= (byte) ipArr[i] & 255;        }        return ipInt;    }    public int[] intToIp(int ipInt) {        int[] ipArr = new int[4];        for (int i = 0; i < 4; i++) {            ipArr[3 - i] ^= (byte) ipInt & 255;            ipInt >>>= 8;        }        return ipArr;    }    private int byteToInt(byte[] bytes) {//        return Bytes.toInt(bytes, 0);        int n = 0;        int offset = 0;        int length = 4;        for (int i = offset; i < offset + length; ++i) {            n <<= 8;            n ^= bytes[i] & 255;        }        return n;    }    private byte[] intToByte(int val) {        int offset = 0;        byte[] bytes = new byte[4];        for (int i = offset + 3; i > offset; --i) {            bytes[i] = (byte) val;            val >>>= 8;        }        bytes[offset] = (byte) val;        return bytes;    }}