常用方法，判斷一個ip是否在指定的ip范圍內，范圍可能包括起始ip范圍或者掩碼形式，無其它依賴，

package com.yk.ip;import java.math.BigInteger;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;public class IpUtil {/*** 判斷目標ip是否在ip范圍內(起始ip范圍),支持ipv6* @param ipAddress 目標ip* @param startIp 開始ip* @param endIp 結束ip* @return boolean* @throws UnknownHostException 異常*/public static boolean isInRange(String ipAddress,String startIp,String endIp) throws UnknownHostException {InetAddress address = InetAddress.getByName(ipAddress);InetAddress startAddress = InetAddress.getByName(startIp);InetAddress endAddress = InetAddress.getByName(endIp);BigInteger start = new BigInteger(1, startAddress.getAddress());BigInteger end = new BigInteger(1, endAddress.getAddress());BigInteger target = new BigInteger(1, address.getAddress());int st = start.compareTo(target);int te = target.compareTo(end);return (st <= 0) && (te <= 0);}/*** 判斷目標ip是否在ip范圍內(掩碼),支持ipv6* @param ipAddress 目標ip* @param ipWithMask 帶掩碼ip* @return boolean* @throws UnknownHostException 異常*/public static boolean isInRange(String ipAddress,String ipWithMask) throws UnknownHostException {if (ipWithMask.contains("/")) {String addressPart = ipWithMask.substring(0, ipWithMask.indexOf("/"));String networkPart = ipWithMask.substring(ipWithMask.indexOf("/") + 1);ByteBuffer maskBuffer;int targetSize;InetAddress inetAddress = InetAddress.getByName(addressPart);if (inetAddress.getAddress().length == 4) {maskBuffer = ByteBuffer.allocate(4).putInt(-1);targetSize = 4;} else {maskBuffer = ByteBuffer.allocate(16).putLong(-1L).putLong(-1L);targetSize = 16;}BigInteger mask = (new BigInteger(1, maskBuffer.array())).not().shiftRight(Integer.parseInt(networkPart));ByteBuffer buffer = ByteBuffer.wrap(inetAddress.getAddress());BigInteger ipVal = new BigInteger(1, buffer.array());BigInteger startIp = ipVal.and(mask);BigInteger endIp = startIp.add(mask.not());byte[] startIpArr = toBytes(startIp.toByteArray(), targetSize);byte[] endIpArr = toBytes(endIp.toByteArray(), targetSize);InetAddress startAddress = InetAddress.getByAddress(startIpArr);InetAddress endAddress = InetAddress.getByAddress(endIpArr);return isInRange(ipAddress, startAddress.getHostAddress(), endAddress.getHostAddress());} else {throw new IllegalArgumentException("not an valid CIDR format!");}}private static byte[] toBytes(byte[] array, int targetSize) {int counter = 0;List<Byte> newArr = new ArrayList<Byte>();while (counter < targetSize && (array.length - 1 - counter >= 0)) {newArr.add(0, array[array.length - 1 - counter]);counter++;}int size = newArr.size();for (int i = 0; i < (targetSize - size); i++) {newArr.add(0, (byte) 0);}byte[] ret = new byte[newArr.size()];for (int i = 0; i < newArr.size(); i++) {ret[i] = newArr.get(i);}return ret;}
}