Why the UnknownHostException happened in Android by using InetAddress.getByName?

Question

I am developing in Android , and I want to get the IP address via domain name.

I have a WiFi device , the WiFi device join to the WiFi network same as my computer.

And the domain name of WiFi device is "abc.local" , I can ping "abc.local" success via my computer.

But It got the java.net.UnknownHostException: Unable to resolve host "abc.local": No address associated with hostname when I use the following code in Android, .

               new Thread(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            InetAddress address = InetAddress.getByName("abc.local");
                        }
                        catch(Exception e) {
                            Log.d(TAG,"mConnectionMode error = " + e);
                        }
                    }
                }).start();

I also add the following permission in AndroidMainifest.xml

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Why the Android device can not get the ip Address via domain name ?

Thanks in advance.

Can you reach this host using for example web browser on the phone? — Bersh, Jan 04 '16 at 10:32
I think you need to place `http` or `https` prior to your web address. — Madhukar Hebbar, Jan 04 '16 at 10:32
@Bersh I can not find anything on my phone via Google Chrome — Wun, Jan 04 '16 at 10:40
@MadhukarHebbar I have try `InetAddress.getByName("http://abc.local");` , it is the same. — Wun, Jan 04 '16 at 10:40
Make sure wifi is able to connect internet [read this](http://stackoverflow.com/q/3314137/4596556) — Madhukar Hebbar, Jan 04 '16 at 10:46

score 0 · Answer 1 · answered Jan 04 '16 at 11:45

How did you set a domain name for a device?

When checking for IP adresses, the device checks with the DNS server for a resolution. I'm having a hunch that you just added abc.local to your hosts file on your computer, and that's why it is working. But that will only work on that computer.

If you could give us some more details how you have set this up, maybe we can help you.

Why the UnknownHostException happened in Android by using InetAddress.getByName?

1 Answers1