Java中的IPv6可用性

是的;您只需循环访问接口,然后检查它们中是否有一个不是循环回的IPv6地址。

final Enumeration<NetworkInterface> e = NetworkInterface.getNetworkInterfaces();
while (e.hasMoreElements()) {
    final Iterator<InterfaceAddress> e2 = e.nextElement().getInterfaceAddresses().iterator();
    while (e2.hasNext()) {
        final InetAddress ip = e2.next().getAddress();
        if (ip.isLoopbackAddress() || ip instanceof Inet4Address){
            continue;
        }
        return true;
    }
}
return false;

上面的函数版本只是第一个接口,而不是全部迭代。

private static boolean supportsIPv6() throws SocketException {
    return Collections.list(NetworkInterface.getNetworkInterfaces()).stream()
            .map(NetworkInterface::getInterfaceAddresses)
            .flatMap(Collection::stream)
            .map(InterfaceAddress::getAddress)
            .anyMatch(((Predicate<InetAddress>) InetAddress::isLoopbackAddress).negate().and(address -> address instanceof Inet6Address));
}

如果您想以更实用的方式实现上述功能,可以检查这个小助手方法。尽管它使用流、函数和lambdas,但它确实做了上面提到的事情。

private static boolean supportsIPv6() throws SocketException {
    return Stream.of(NetworkInterface.getNetworkInterfaces().nextElement())
                 .map(NetworkInterface::getInterfaceAddresses)
                 .flatMap(Collection::stream)
                 .map(InterfaceAddress::getAddress)
                 .anyMatch(((Predicate<InetAddress>) InetAddress::isLoopbackAddress).negate().and(address -> address instanceof Inet6Address));

}