使用主机名时 HttpURLConnection 无法解析主机

Question

I've checked most of the topics about the same problem, but I couldn't find a solution.

My Android app connects to a WCF service using the HttpURLConnection and it works fine when I use the IP address of the machine that hosts the service. However, when I replace it with a host name it can not connect. The connection method that I have is quite standard:

public static String getData(RequestPackage requestPackage) {
        BufferedReader reader = null;
        HttpURLConnection con = null;
        String uri = requestPackage.getUri();
        String response = "";

        try {
            URL url = new URL(uri);
            con = (HttpURLConnection) url.openConnection();
            con.setReadTimeout(requestPackage.getReadTimeout());
            con.setConnectTimeout(requestPackage.getConTimeout());
            con.setRequestMethod(requestPackage.getMethod());
            con.setDoInput(requestPackage.isDoInput());
            con.setDoOutput(requestPackage.isDoOutput());

            JSONObject user = new JSONObject(requestPackage.getParams());

            OutputStream os = con.getOutputStream(); // the exception is thrown here
            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
            writer.write(user.toString());
            writer.flush();
            writer.close();
            os.close();

            // Get response from the service
            int responseCode = con.getResponseCode();

            if (responseCode == HttpURLConnection.HTTP_OK) {
                // more code...
            }else
                // more code

The exception is:

java.net.UnknownHostException: Unable to resolve host "myHostname": No address associated with hostname"

myHostname is my actual host name.

It works fine when I use the same url on my PC (both with the IP and with the host name).

On the phone it works only if i am using the IP. Both in the app or in the mobile browser.

I have added the necessary permissions in the AndroidManifest.xml :

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />

Could it be something with the permissions to the server that hosts the service? It's an internal server and all machines are connected to an internal Wi-Fi.network. But it works with the IP...

EDIT: I forgot to mention that I am using a physical device instead of the emulator.

Answer 1

It is all right. Android tells you that the phone cannot resolve the name "myHostname". It depends on the topology of your.network. I think that the phone is connected with wifi on an access point that has a wired connection to the lan on which there are you pc and your myHostname host. Your pc got a dns server on its lan connection or just resolve the name with lan broadcasting. Surely you have not configured a dns server on the connection in use on your phone. If you have a dns server on your lan, than set it on the connection, otherwise I don't think that a phone can resolve by broadcast.