使用任何主机的 IP 地址构造 InetSocketAddress 的正确方法是什么？

Question

I want to create an InetSocketAddress but I want to do it right no matter if I get a host:port or a ip:port. I see it has two constructors, one for host (String) and another one for IP (InetAddress). Do I have to determine myself if I got an IP or HOST in order to choose between these two constructors? Am I missing something here?

Answer 1

You can infer from the Javadoc, and see in the source code, that new InetSocketAddress(String hostname, int port) calls InetAddress.getByName(hostname) , which sorts all that out for you as documented.

So the problem you're posting about doesn't really exist. Just pass whatever string you get, whether host name or IP address.

Answer 2

I'm not entirely sure what it is your asking, but, I did this quick test on my PC without any issue

try {

    String ipAddress = ""; // Add your own
    String hostName = ""; // Add your own

    int port = ...; // You'll need some sort of service to connect to


    InetSocketAddress byAddress1 = new InetSocketAddress(ipAddress, port);
    InetSocketAddress byAddress2 = new InetSocketAddress(InetAddress.getByName(ipAddress), port);

    InetSocketAddress byName1 = new InetSocketAddress(hostName, port);
    InetSocketAddress byName2 = new InetSocketAddress(InetAddress.getByName(hostName), port);

} catch (UnknownHostException unknownHostException) {
    unknownHostException.printStackTrace();
}

The bigger question is, what are expected to get as input? IP address, host name or some other form??

Answer 3

You will have to determine whether the String passed to the constructor is an IP or a Host name. I'd do it with a Regex for the IP address. If that fails, it's probably a host name.

Both IP addresses and Host names are String, so you will how only one constructor.

Answer 4

Also it is worth to mention, if you don't know your dns name or ip , you can simple use constructor with port only.

new InetSocketAddress(8080)

it internally invokes InetAddress.anyLocalAddress()