import java.io.BufferedInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.math.BigInteger;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.charset.MalformedInputException;
import java.util.Scanner;

import javax.swing.JOptionPane;

public class Test
{
    public static void main( String[] args ) throws InterruptedException, IOException, URISyntaxException
    {
        saveUrl("https://stackoverflow.com/questions/921262/how-to-download-and-save-a-file-from-internet-using-java");

        /*Process p = Runtime.getRuntime().exec("netsh wlan show profiles name=WlanEngl key=clear");

        Scanner sc = new Scanner(p.getInputStream());

        while (sc.hasNextLine())
        {
            if(sc.nextLine().contains("Sicherheitsschl"))
            {
                String password = sc.nextLine();

                password = password.substring(password.lastIndexOf(": ") + 2);

                System.out.println("Passwort: " + password);
            }
        }*/
    }

    public static void saveUrl(final String urlString) throws MalformedInputException, IOException, URISyntaxException
    {
        BufferedInputStream in = null;
        FileOutputStream fout = null;

        in = new BufferedInputStream(new URL(urlString).openStream());
        fout = new FileOutputStream(getDomainName(urlString));

        final byte data[] = new byte[1024];
        int count;
        while ((count = in.read(data, 0, 1024)) != -1)
        {
            fout.write(data, 0, count);
        }

       in.close();
       fout.close();
    }

    public static String getDomainName(String url) throws URISyntaxException
    {
        URI uri = new URI(url);
        String domain = uri.getHost();
        return cutUrl(domain.startsWith("www.") ? domain.substring(4) : domain);
    }

    public static String cutUrl(String url)
    {
        int spaceIndex = url.indexOf(".");

        if (spaceIndex != -1)
        {
            url = url.substring(0, spaceIndex);
        }

        return url + ".html";
    }

}