Java 检查IPv6地址的合法性

由于IPv4资源即将耗尽，IPv6将要正式启用，这是大势所趋。

一些现有的服务和应用逐步要对IPv6支持，目前还处在过渡阶段。

提前了解一些IPv6的知识，还是有必要的。

如何判断一个IP地址，是否为IPv6地址呢？

以下代码是用Java实现的，用于校验IPv6地址合法性。

代码如下：

import java.text.Normalizer;
import java.text.Normalizer.Form;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class IPV6Check {
 
    public static void main(String[] args) {
        String ipv6_1 = "2019:db8:a583:64:c68c:d6df:600c:ee9a";
        String ipv6_2 = "2019:db8:a583::9e42:be55:53a7";
        String ipv6_3 = "2019:db8:a583:::9e42:be55:53a7";
        String ipv6_4 = "1:2:3:4:5::192.168.254.254";
        String ipv6_5 = "ABCD:910A:2222:5498:8475:1111:3900:2020";
        String ipv6_6 = "1030::C9B4:FF12:48AA:1A2B";
        String ipv6_7 = "2019:0:0:0:0:0:0:1";
        String ipv6_8 = "::0:0:0:0:0:0:1";
        String ipv6_9 = "2019:0:0:0:0::";
        String ipv6_10= "2048:877e:31::7";

        String resultLine = "\n==> ";
        String splitLine = "\n----------------------------------------------------\n";
        System.out.println(ipv6_1 + resultLine + isValidIpv6Addr(ipv6_1) + splitLine);
        System.out.println(ipv6_2 + resultLine + isValidIpv6Addr(ipv6_2) + splitLine);
        System.out.println(ipv6_3 + resultLine + isValidIpv6Addr(ipv6_3) + splitLine);
        System.out.println(ipv6_4 + resultLine + isValidIpv6Addr(ipv6_4) + splitLine);
        System.out.println(ipv6_5 + resultLine + isValidIpv6Addr(ipv6_5) + splitLine);
        System.out.println(ipv6_6 + resultLine + isValidIpv6Addr(ipv6_6) + splitLine);
        System.out.println(ipv6_7 + resultLine + isValidIpv6Addr(ipv6_7) + splitLine);
        System.out.println(ipv6_8 + resultLine + isValidIpv6Addr(ipv6_8) + splitLine);
        System.out.println(ipv6_9 + resultLine + isValidIpv6Addr(ipv6_9) + splitLine);
        System.out.println(ipv6_10 + resultLine + isValidIpv6Addr(ipv6_10) + splitLine);
    }

    /**
     * 校验IPv6地址的合法性
     * @param ipAddr
     * @return
     */
    public static boolean isValidIpv6Addr(String ipAddr) {
 
        String regex = "(^((([0-9A-Fa-f]{1,4}:){7}(([0-9A-Fa-f]{1,4}){1}|:))"
                + "|(([0-9A-Fa-f]{1,4}:){6}((:[0-9A-Fa-f]{1,4}){1}|"
                + "((22[0-3]|2[0-1][0-9]|[0-1][0-9][0-9]|"
                + "([0-9]){1,2})([.](25[0-5]|2[0-4][0-9]|"
                + "[0-1][0-9][0-9]|([0-9]){1,2})){3})|:))|"
                + "(([0-9A-Fa-f]{1,4}:){5}((:[0-9A-Fa-f]{1,4}){1,2}|"
                + ":((22[0-3]|2[0-1][0-9]|[0-1][0-9][0-9]|"
                + "([0-9]){1,2})([.](25[0-5]|2[0-4][0-9]|"
                + "[0-1][0-9][0-9]|([0-9]){1,2})){3})|:))|"
                + "(([0-9A-Fa-f]{1,4}:){4}((:[0-9A-Fa-f]{1,4}){1,3}"
                + "|:((22[0-3]|2[0-1][0-9]|[0-1][0-9][0-9]|"
                + "([0-9]){1,2})([.](25[0-5]|2[0-4][0-9]|[0-1][0-9][0-9]|"
                + "([0-9]){1,2})){3})|:))|(([0-9A-Fa-f]{1,4}:){3}((:[0-9A-Fa-f]{1,4}){1,4}|"
                + ":((22[0-3]|2[0-1][0-9]|[0-1][0-9][0-9]|"
                + "([0-9]){1,2})([.](25[0-5]|2[0-4][0-9]|"
                + "[0-1][0-9][0-9]|([0-9]){1,2})){3})|:))|"
                + "(([0-9A-Fa-f]{1,4}:){2}((:[0-9A-Fa-f]{1,4}){1,5}|"
                + ":((22[0-3]|2[0-1][0-9]|[0-1][0-9][0-9]|"
                + "([0-9]){1,2})([.](25[0-5]|2[0-4][0-9]|"
                + "[0-1][0-9][0-9]|([0-9]){1,2})){3})|:))"
                + "|(([0-9A-Fa-f]{1,4}:){1}((:[0-9A-Fa-f]{1,4}){1,6}"
                + "|:((22[0-3]|2[0-1][0-9]|[0-1][0-9][0-9]|"
                + "([0-9]){1,2})([.](25[0-5]|2[0-4][0-9]|"
                + "[0-1][0-9][0-9]|([0-9]){1,2})){3})|:))|"
                + "(:((:[0-9A-Fa-f]{1,4}){1,7}|(:[fF]{4}){0,1}:((22[0-3]|2[0-1][0-9]|"
                + "[0-1][0-9][0-9]|([0-9]){1,2})"
                + "([.](25[0-5]|2[0-4][0-9]|[0-1][0-9][0-9]|([0-9]){1,2})){3})|:)))$)";
 
        if (ipAddr == null) {
            System.out.println("IPv6 address is null ");
            return false;
        }
        ipAddr = Normalizer.normalize(ipAddr, Form.NFKC);
        Pattern pattern = Pattern.compile(regex);
        Matcher matcher = pattern.matcher(ipAddr);
 
        boolean match = matcher.matches();
        if (!match) {
             System.out.println("Invalid IPv6 address = " + ipAddr);
        }
 
        return match;
    }
 
}

运行结果如下：

2019:db8:a583:64:c68c:d6df:600c:ee9a
==> true
----------------------------------------------------

2019:db8:a583::9e42:be55:53a7
==> true
----------------------------------------------------

Invalid IPv6 address = 2019:db8:a583:::9e42:be55:53a7
2019:db8:a583:::9e42:be55:53a7
==> false
----------------------------------------------------

1:2:3:4:5::192.168.254.254
==> true
----------------------------------------------------

ABCD:910A:2222:5498:8475:1111:3900:2020
==> true
----------------------------------------------------

1030::C9B4:FF12:48AA:1A2B
==> true
----------------------------------------------------

2019:0:0:0:0:0:0:1
==> true
----------------------------------------------------

::0:0:0:0:0:0:1
==> true
----------------------------------------------------

2019:0:0:0:0::
==> true
----------------------------------------------------

2048:877e:31::7
==> true
----------------------------------------------------