在Java中获取eth0接口的IP地址仅返回IPv6地址而不返回IPv4

Question

我编写了以下代码，以获取我在计算机上使用的eth0接口的IPv4地址。但是，fe80:x:x:x:xxx:xxxx:xxxx:xxxx由于我正在查找IPv4地址，因此代码仅查找未返回的代码。

这是代码。

    interfaceName = "eth0";
    NetworkInterface networkInterface = NetworkInterface.getByName(interfaceName);
    Enumeration<InetAddress> inetAddress = networkInterface.getInetAddresses();
    InetAddress currentAddress;
    currentAddress = inetAddress.nextElement();
    while(inetAddress.hasMoreElements())
    {
        System.out.println(currentAddress);
        if(currentAddress instanceof Inet4Address && !currentAddress.isLoopbackAddress())
        {
            ip = currentAddress.toString();
            break;
        }
        currentAddress = inetAddress.nextElement();
    }

Answer 1

它弄乱了获取下一个元素的逻辑。inetAddress在while比较运行之前，我已经获取了下一个元素。从而使元素不再存在。

下面的代码已经修复了逻辑

    interfaceName = "eth0";
    NetworkInterface networkInterface = NetworkInterface.getByName(interfaceName);
    Enumeration<InetAddress> inetAddress = networkInterface.getInetAddresses();
    InetAddress currentAddress;
    currentAddress = inetAddress.nextElement();
    while(inetAddress.hasMoreElements())
    {
        currentAddress = inetAddress.nextElement();
        if(currentAddress instanceof Inet4Address && !currentAddress.isLoopbackAddress())
        {
            ip = currentAddress.toString();
            break;
        }
    }