看阿里的代码Java是如何获取本地IP地址的

在服务器开发过程中，有时候为了方便，可以使用代码获取本机的IP地址，而不需要再手动配置了。阿里的代码一直是业界的标准，在看RocketMQ的源码的时候，看到了他们的一个获取本机IP地址的工具类，在这里给大家分享出来，有时候的拿来就可以使用。

public static String getLocalAddress() {
        try {
            // Traversal Network interface to get the first non-loopback and non-private address
            Enumeration<NetworkInterface> enumeration = NetworkInterface.getNetworkInterfaces();
            ArrayList<String> ipv4Result = new ArrayList<String>();
            ArrayList<String> ipv6Result = new ArrayList<String>();
            while (enumeration.hasMoreElements()) {
                final NetworkInterface networkInterface = enumeration.nextElement();
                final Enumeration<InetAddress> en = networkInterface.getInetAddresses();
                while (en.hasMoreElements()) {
                    final InetAddress address = en.nextElement();
                    if (!address.isLoopbackAddress()) {
                        if (address instanceof Inet6Address) {
                            ipv6Result.add(normalizeHostAddress(address));
                        } else {
                            ipv4Result.add(normalizeHostAddress(address));
                        }
                    }
                }
            }

            // prefer ipv4
            if (!ipv4Result.isEmpty()) {
                for (String ip : ipv4Result) {
                    if (ip.startsWith("127.0") || ip.startsWith("192.168")) {
                        continue;
                    }

                    return ip;
                }

                return ipv4Result.get(ipv4Result.size() - 1);
            } else if (!ipv6Result.isEmpty()) {
                return ipv6Result.get(0);
            }
            //If failed to find,fall back to localhost
            final InetAddress localHost = InetAddress.getLocalHost();
            return normalizeHostAddress(localHost);
        } catch (Exception e) {
            log.error("Failed to obtain local address", e);
        }

        return null;
    }

    public static String normalizeHostAddress(final InetAddress localHost) {
        if (localHost instanceof Inet6Address) {
            return "[" + localHost.getHostAddress() + "]";
        } else {
            return localHost.getHostAddress();
        }
    }