JAVA中IP和整数相互转化

一、基本知识点

IP ——> 整数：

• 把IP地址转化为字节数组
• 通过左移位（<<）、与（&）、或（|）这些操作转为int

整数 ——> IP：

• 将整数值进行右移位操作（>>>），右移24位，再进行与操作符（&）0xFF，得到的数字即为第一段IP。
• 将整数值进行右移位操作（>>>），右移16位，再进行与操作符（&）0xFF，得到的数字即为第二段IP。
• 将整数值进行右移位操作（>>>），右移8位，再进行与操作符（&）0xFF，得到的数字即为第三段IP。
• 将整数值进行与操作符（&）0xFF，得到的数字即为第四段IP。

二、java代码示例

    IPv4Util.java package michael.utils;

import java.net.InetAddress;

public class IPv4Util {

    private final static int INADDRSZ = 4;

    public static byte[] ipToBytesByInet(String ipAddr) {

        try {

            return InetAddress.getByName(ipAddr).getAddress();

        } catch (Exception e) {

            throw new IllegalArgumentException(ipAddr + " is invalid IP");

        }

    } JTA实践:Spring+ATOMIKOS

    public static byte[] ipToBytesByReg(String ipAddr) {

        byte[] ret = new byte[4];

        try {

            String[] ipArr = ipAddr.split("\\.");

            ret[0] = (byte) (Integer.parseInt(ipArr[0]) & 0xFF);

            ret[1] = (byte) (Integer.parseInt(ipArr[1]) & 0xFF);

            ret[2] = (byte) (Integer.parseInt(ipArr[2]) & 0xFF);

            ret[3] = (byte) (Integer.parseInt(ipArr[3]) & 0xFF);

            return ret;

        } catch (Exception e) {

            throw new IllegalArgumentException(ipAddr + " is invalid IP");

        }

    }

    public static String bytesToIp(byte[] bytes) {

        return new StringBuffer().append(bytes[0] & 0xFF).append('.').append(

                bytes[1] & 0xFF).append('.').append(bytes[2] & 0xFF)

                .append('.').append(bytes[3] & 0xFF).toString();

    }

    public static int bytesToInt(byte[] bytes) {

        int addr = bytes[3] & 0xFF;

        addr |= ((bytes[2] << 8) & 0xFF00);

        addr |= ((bytes[1] << 16) & 0xFF0000);

        addr |= ((bytes[0] << 24) & 0xFF000000);

        return addr;

    }

    public static int ipToInt(String ipAddr) {

        try {

            return bytesToInt(ipToBytesByInet(ipAddr));

        } catch (Exception e) {

            throw new IllegalArgumentException(ipAddr + " is invalid IP");

        }

    }

    public static byte[] intToBytes(int ipInt) {

        byte[] ipAddr = new byte[INADDRSZ];

        ipAddr[0] = (byte) ((ipInt >>> 24) & 0xFF);

        ipAddr[1] = (byte) ((ipInt >>> 16) & 0xFF);

        ipAddr[2] = (byte) ((ipInt >>> 8) & 0xFF);

        ipAddr[3] = (byte) (ipInt & 0xFF);

        return ipAddr;

    }

    public static String intToIp(int ipInt) {

        return new StringBuilder().append(((ipInt >> 24) & 0xff)).append('.')

                .append((ipInt >> 16) & 0xff).append('.').append(

                        (ipInt >> 8) & 0xff).append('.').append((ipInt & 0xff))

                .toString();

    }

    public static int[] getIPIntScope(String ipAndMask) {

        String[] ipArr = ipAndMask.split("/");

        if (ipArr.length != 2) {

            throw new IllegalArgumentException("invalid ipAndMask with: "

                    + ipAndMask);

        }

        int netMask = Integer.valueOf(ipArr[1].trim());

        if (netMask < 0 || netMask > 31) {

            throw new IllegalArgumentException("invalid ipAndMask with: "

                    + ipAndMask);

        }

        int ipInt = IPv4Util.ipToInt(ipArr[0]);

        int netIP = ipInt & (0xFFFFFFFF << (32 - netMask));

        int hostScope = (0xFFFFFFFF >>> netMask);

        return new int[] { netIP, netIP + hostScope };

    }

    public static String[] getIPAddrScope(String ipAndMask) {

        int[] ipIntArr = IPv4Util.getIPIntScope(ipAndMask);

        return new String[] { IPv4Util.intToIp(ipIntArr[0]),

                IPv4Util.intToIp(ipIntArr[0]) };

    }

    public static int[] getIPIntScope(String ipAddr, String mask) {

        int ipInt;

        int netMaskInt = 0, ipcount = 0;

        try {

            ipInt = IPv4Util.ipToInt(ipAddr);

            if (null == mask || "".equals(mask)) {

                return new int[] { ipInt, ipInt };

            }

            netMaskInt = IPv4Util.ipToInt(mask);

            ipcount = IPv4Util.ipToInt("255.255.255.255") - netMaskInt;

            int netIP = ipInt & netMaskInt;

            int hostScope = netIP + ipcount;

            return new int[] { netIP, hostScope };

        } catch (Exception e) {

            throw new IllegalArgumentException("invalid ip scope express  ip:"

                    + ipAddr + "  mask:" + mask);

        }

    }

    public static String[] getIPStrScope(String ipAddr, String mask) {

        int[] ipIntArr = IPv4Util.getIPIntScope(ipAddr, mask);

        return new String[] { IPv4Util.intToIp(ipIntArr[0]),

                IPv4Util.intToIp(ipIntArr[0]) };

    }

    public static void main(String[] args) throws Exception {

        String ipAddr = "192.168.8.1";

        byte[] bytearr = IPv4Util.ipToBytesByInet(ipAddr);

        StringBuffer byteStr = new StringBuffer();

        for (byte b : bytearr) {

            if (byteStr.length() == 0) {

                byteStr.append(b);

            } else {

                byteStr.append("," + b);

            }

        }

        System.out.println("IP: " + ipAddr + " ByInet --> byte[]: [ " + byteStr

                + " ]");

        bytearr = IPv4Util.ipToBytesByReg(ipAddr);

        byteStr = new StringBuffer();

        for (byte b : bytearr) {

            if (byteStr.length() == 0) {

                byteStr.append(b);

            } else {

                byteStr.append("," + b);

            }

        }

        System.out.println("IP: " + ipAddr + " ByReg  --> byte[]: [ " + byteStr

                + " ]");

        System.out.println("byte[]: " + byteStr + " --> IP: "

                + IPv4Util.bytesToIp(bytearr));

        int ipInt = IPv4Util.ipToInt(ipAddr);

        System.out.println("IP: " + ipAddr + "  --> int: " + ipInt);

        System.out.println("int: " + ipInt + " --> IP: "

                + IPv4Util.intToIp(ipInt));

        String ipAndMask = "192.168.1.1/24";

        int[] ipscope = IPv4Util.getIPIntScope(ipAndMask);

        System.out.println(ipAndMask + " --> int地址段：[ " + ipscope[0] + ","

                + ipscope[1] + " ]");

        System.out.println(ipAndMask + " --> IP 地址段：[ "

                + IPv4Util.intToIp(ipscope[0]) + ","

                + IPv4Util.intToIp(ipscope[1]) + " ]");

        String ipAddr1 = "192.168.1.1", ipMask1 = "255.255.255.0";

        int[] ipscope1 = IPv4Util.getIPIntScope(ipAddr1, ipMask1);

        System.out.println(ipAddr1 + " , " + ipMask1 + "  --> int地址段 ：[ "

                + ipscope1[0] + "," + ipscope1[1] + " ]");

        System.out.println(ipAddr1 + " , " + ipMask1 + "  --> IP地址段 ：[ "

                + IPv4Util.intToIp(ipscope1[0]) + ","

                + IPv4Util.intToIp(ipscope1[1]) + " ]");

    }

}