<dependency>
      <groupId>commons-validator</groupId>
      <artifactId>commons-validator</artifactId>
      <version>1.6</version>
    </dependency>

    private static final InetAddressValidator VALIDATOR = InetAddressValidator.getInstance();
    public static boolean isValidIPV4ByValidator(String inetAddress) {
        return VALIDATOR.isValidInet4Address(inetAddress);
    }

    public static boolean isValidIPV6ByValidator(String inetAddress) {
        return VALIDATOR.isValidInet6Address(inetAddress);
    }

    public static boolean isValidIPV6ByValidator(String inetAddress) {
        return VALIDATOR.isValid(inetAddress);
    }

    <dependency>
      <groupId>com.google.guava</groupId>
      <artifactId>guava</artifactId>
      <version>30.0-jre</version>
    </dependency>

    public static boolean isValidByGuava(String ip) {
        return InetAddresses.isInetAddress(ip);
    }

    private static final String OWASP_IPV4_REGEX =
            "^(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\." +
                    "(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\." +
                    "(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\." +
                    "(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$";

    private static final Pattern OWASP_IPv4_PATTERN = Pattern.compile(OWASP_IPV4_REGEX);

    public static boolean isValidIPV4ByOWASP(String ip) {
        if (ip == null || ip.trim().isEmpty()) {
            return false;
        }
        return OWASP_IPv4_PATTERN.matcher(ip).matches();
    }

    private static final String IPV4_REGEX =
            "^(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})$";

    private static final Pattern IPv4_PATTERN = Pattern.compile(IPV4_REGEX);

    public static boolean isValidIPV4ByCustomRegex(String ip) {
        if (ip == null || ip.trim().isEmpty()) {
            return false;
        }
        if (!IPv4_PATTERN.matcher(ip).matches()) {
            return false;
        }
        String[] parts = ip.split("\\.");
        try {
            for (String segment : parts) {
                if (Integer.parseInt(segment) > 255 ||
                        (segment.length() > 1 && segment.startsWith("0"))) {
                    return false;
                }
            }
        } catch (NumberFormatException e) {
            return false;
        }
        return true;
    }

    public static boolean isValidIPV4ByJDK(String ip) {
        try {
            return Inet4Address.getByName(ip)
                    .getHostAddress().equals(ip);
        } catch (UnknownHostException ex) {
            return false;
        }
    }

    private static List<String> generateFakeIp(int capacity) {
        List<String> ipList = new ArrayList<String>(capacity);
        for (int i = 0; i < capacity; i++) {
            int parts = boundRandom(1, 3);
            if (chanceOf50()) { //each ip has 50% chance to be 4 parts
                parts = 4;
            }
            StringBuilder sbBuilder = new StringBuilder();
            for (int j = 0; j < parts; j++) {
                if (sbBuilder.length() > 0) {
                    sbBuilder.append(".");
                }
                StringBuilder stringBuilder = new StringBuilder();
                if (chanceOf10()) { //each part has 10% chance to generate a fake number
                    stringBuilder.append('a');
                } else { //each part has 90% chance to generate the correct number
                    stringBuilder.append(boundRandom(0, 255));
                }
                sbBuilder.append(stringBuilder);
            }
            ipList.add(sbBuilder.toString());
        }
        return ipList;
    }
    
    private static long correctCount(List<String> ipList) {
        return ipList.stream().filter(ip -> isValidIPV4ByCustomRegex(ip)).collect(Collectors.toList()).size();
    }
    
    // 50% chance
    private static boolean chanceOf50() {
        return boundRandom(0, 9) < 5;
    }

    // 10% chance
    private static boolean chanceOf10() {
        return boundRandom(0, 9) < 1;
    }

    private static Random random = new Random();
    // random int between [start, end], both start and end are included
    private static int boundRandom(int start, int end) {
        return start + random.nextInt(end);
    }

    public static void performanceTest() {
        List<String> ipList = generateFakeIp(100);
        double chance = correctCount(ipList);
        System.out.println("start testing, correct ip count is : " + chance);
        long t1 = System.currentTimeMillis();
        ipList.stream().forEach( ip-> isValidIPV4ByCustomRegex(ip));
        long t2 = System.currentTimeMillis();
        ipList.stream().forEach( ip-> isValidIPV4ByJDK(ip));
        long t3 = System.currentTimeMillis();
        System.out.println("isValidIPV4ByCustomRegex cost time : " + (t2-t1));
        System.out.println("isValidIPV4ByJDK cost time : " + (t3-t2));
    }