Get public ip associated with the private ip in Java using http request to ifconfig.co

Question

I have written a code to get all the private ips associated with each interface. I'm storing all the private ips in ArrayList ips.

List<String> ips = new ArrayList<>();
for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements();) {
       NetworkInterface intf = en.nextElement();
       for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements(); ) {
                    ips.add(enumIpAddr.nextElement().toString().replace("/", ""));
       }
}

Now I want to iterate over the List ips and want to call the http request to get the public ip. Below is the linux curl command that will return public ip associated with the private ip 10.74.4.11.

curl -i --interface 10.74.4.11 "ifconfig.co"

I just want convert this linux command to java http request which I can use in my program.

Answer 1

This method uses Java Runtime API to execute the command and then adds the found public ip to the hashmap as a value to the internalIp key. So finally you can find the desired public ip by searching through the hashmap "ips.get("internalIp")"

private static void getIps() throws IOException {
            Map<String, String> ips = new HashMap<>();
            for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements();) {
                NetworkInterface intf = en.nextElement();
                for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements(); ) {
                    ips.put(enumIpAddr.nextElement().toString().replace("/", ""), "");
                }
            }
            for (String ip: ips.keySet())
            {
                String command="curl --interface "+ ip+" ifconfig.co";
                System.out.println("Excecuting: "+command);
                Process process = Runtime.getRuntime().exec(command);
                try {
                    process.waitFor();
                    final int exitValue = process.waitFor();
                    if (exitValue == 0) {
                        System.out.println("Successfully executed the command: " + command);
                       List<String> result = new BufferedReader(new InputStreamReader(process.getInputStream()))
                        .lines().collect(Collectors.toList());
                       ips.put(ip, result.get(result.size()-1));//the public IP will be the last item in the result stream
                    }
                    else {
                        System.out.println("Failed to execute the following command: " + command + " due to the following error(s):");
                        try (final BufferedReader b = new BufferedReader(new InputStreamReader(process.getErrorStream()))) {
                            String line;
                            if ((line = b.readLine()) != null)
                                System.out.println(line);
                        } catch (final IOException e) {
                            e.printStackTrace();
                        }
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }



            }
            System.out.println(ips);

        }