Java代碼中對IP進行白名單驗證

來自：https://www.cnblogs.com/shinubi/p/6723003.html

public class ipUtil {

    // IP的正則,這個正則不能驗證第一組數字為0的情況
//    private static Pattern pattern = Pattern
//            .compile("(1\\d{1,2}|2[0-4]\\d|25[0-5]|\\d{1,2})\\."
//                    + "(1\\d{1,2}|2[0-4]\\d|25[0-5]|\\d{1,2})\\."
//                    + "(1\\d{1,2}|2[0-4]\\d|25[0-5]|\\d{1,2})\\."
//                    + "(1\\d{1,2}|2[0-4]\\d|25[0-5]|\\d{1,2})");
    private static Pattern pattern = Pattern
            .compile("([1-9]\\d?|1\\d{2}|2[01]\\d|22[0-3])\\."
                    + "(1\\d{1,2}|2[0-4]\\d|25[0-5]|\\d{1,2})\\."
                    + "(1\\d{1,2}|2[0-4]\\d|25[0-5]|\\d{1,2})\\."
                    + "(1\\d{1,2}|2[0-4]\\d|25[0-5]|\\d{1,2})");

    /**
     *
     * getAvaliIpList:(根據IP白名單設置獲取可用的IP列表).
     *
     * @date 2017-4-17 下午02:50:20
     * @return
     */

    private static Set<String> getAvaliIpList(String allowIp) {

        Set<String> ipList = new HashSet<String>();
        for (String allow : allowIp.replaceAll("\\s", "").split(",")) {
            if (allow.indexOf("*") > -1) {
                String[] ips = allow.split("\\.");
                String[] from = new String[] { "0", "0", "0", "0" };
                String[] end = new String[] { "255", "255", "255", "255" };
                List<String> tem = new ArrayList<String>();
                for (int i = 0; i < ips.length; i++)
                    if (ips[i].indexOf("*") > -1) {
                    //todo 直接用等於，不能正確獲取類似192.168.**.*這種格式的ip段
                        tem = complete(ips[i]);
                        from[i] = null;
                        end[i] = null;
                    } else {
                        from[i] = ips[i];
                        end[i] = ips[i];
                    }

                StringBuffer fromIP = new StringBuffer();
                StringBuffer endIP = new StringBuffer();
                for (int i = 0; i < 4; i++)
                    if (from[i] != null) {
                        fromIP.append(from[i]).append(".");
                        endIP.append(end[i]).append(".");
                    } else {
                        fromIP.append("[*].");
                        endIP.append("[*].");
                    }
                fromIP.deleteCharAt(fromIP.length() - 1);
                endIP.deleteCharAt(endIP.length() - 1);

                for (String s : tem) {
                    String ip = fromIP.toString().replace("[*]",
                            s.split(";")[0])
                            + "-"
                            + endIP.toString().replace("[*]", s.split(";")[1]);
                    if (validate(ip)) {
                        ipList.add(ip);
                    }
                }
            } else {
                if (validate(allow)) {
                    ipList.add(allow);
                }
            }

        }

        return ipList;
    }

    /**
     * 對單個IP節點進行范圍限定
     *
     * @param arg
     * @return 返回限定后的IP范圍，格式為List[10;19, 100;199]
     */
    private static List<String> complete(String arg) {
        List<String> com = new ArrayList<String>();
        if (arg.length() == 1) {
            com.add("0;255");
        } else if (arg.length() == 2) {
            String s1 = complete(arg, 1);
            if (s1 != null)
                com.add(s1);
            String s2 = complete(arg, 2);
            if (s2 != null)
                com.add(s2);
        } else {
            String s1 = complete(arg, 1);
            if (s1 != null)
                com.add(s1);
        }
        return com;
    }

    private static String complete(String arg, int length) {
        String from = "";
        String end = "";
        if (length == 1) {
            from = arg.replace("*", "0");
            end = arg.replace("*", "9");
        } else {
            from = arg.replace("*", "00");
            end = arg.replace("*", "99");
        }
        if (Integer.valueOf(from) > 255)
            return null;
        if (Integer.valueOf(end) > 255)
            end = "255";
        return from + ";" + end;
    }

    /**
     * 在添加至白名單時進行格式校驗
     *
     * @param ip
     * @return
     */
    private static boolean validate(String ip) {
        for (String s : ip.split("-"))
            if (!pattern.matcher(s).matches()) {
                return false;
            }
        return true;
    }

    /**
     *
     * checkLoginIP:(根據IP,及可用Ip列表來判斷ip是否包含在白名單之中).
     * @date 2017-4-17 下午03:01:03
     * @param ip
     * @param ipList
     * @return
     */
    private static boolean checkLoginIP(String ip, Set<String> ipList) {
        if (ipList.isEmpty() || ipList.contains(ip))
            return true;
        else {
            for (String allow : ipList) {
                if (allow.indexOf("-") > -1) {
                    String[] from = allow.split("-")[0].split("\\.");
                    String[] end = allow.split("-")[1].split("\\.");
                    String[] tag = ip.split("\\.");

                    // 對IP從左到右進行逐段匹配
                    boolean check = true;
                    for (int i = 0; i < 4; i++) {
                        int s = Integer.valueOf(from[i]);
                        int t = Integer.valueOf(tag[i]);
                        int e = Integer.valueOf(end[i]);
                        if (!(s <= t && t <= e)) {
                            check = false;
                            break;
                        }
                    }
                    if (check) {
                        return true;
                    }
                }
            }
        }
        return false;
    }

    /**
     *
     * checkLoginIP:(根據IP地址，及IP白名單設置規則判斷IP是否包含在白名單).
     * @date 2017-4-17 下午03:01:37
     * @param ip
     * @param ipWhiteConfig
     * @return
     */
    public static boolean checkLoginIP(String ip,String ipWhiteConfig){
        Set<String> ipList = getAvaliIpList(ipWhiteConfig);
        return checkLoginIP(ip, ipList);
    }

    public static void main(String[] args) {

        String ipWhilte = "192.168.1.1," +                 //設置單個IP的白名單
                "192.168.*.2," +                 //設置ip通配符,對一個ip段進行匹配
                "192.168.3.17-192.168.3.38";     //設置一個IP范圍
        boolean flag = checkLoginIP("192.168.2.2",ipWhilte);
        boolean flag2 = checkLoginIP("192.168.1.2",ipWhilte);
        boolean flag3 = checkLoginIP("192.168.3.16",ipWhilte);
        boolean flag4 = checkLoginIP("192.168.3.17",ipWhilte);
        System.out.println(flag);  //true
        System.out.println(flag2);  //false
        System.out.println(flag3);  //false
        System.out.println(flag4);  //true
    }
}