1  import java.io.InputStream;

  2  import java.io.IOException;

  3  import java.io.OutputStream;

  4  import java.io.PrintWriter;

  5  import java.net.HttpURLConnection;

  6  import java.net.URL;

  7  import java.net.URLConnection;

  8  import java.util.Scanner;

  9  

 10  /**

 11     This program demonstrates how to use a URL connection 

 12     to communicate with a web server. Supply the URL on the

 13     command line, for example

 14        java URLGet http://horstmann.com/index.html

 15  */

 16  public class URLGet

 17  {

 18     public static void main(String[] args) throws IOException

 19     {

 20        // Get command line arguments

 21  

 22        String urlString;      

 23        if (args.length == 1)

 24        {

 25           urlString = args[0];

 26        }

 27        else

 28        {

 29           urlString = "http://horstmann.com/";

 30           System.out.println("Using " + urlString);

 31        }

 32  

 33        // Open connection

 34  

 35        URL u = new URL(urlString);

 36        URLConnection connection = u.openConnection();

 37  

 38        // Check if response code is HTTP_OK (200)

 39       

 40        HttpURLConnection httpConnection 

 41              = (HttpURLConnection) connection;

 42        int code = httpConnection.getResponseCode();

 43        String message = httpConnection.getResponseMessage(); 

 44        System.out.println(code + " " + message);

 45        if (code != HttpURLConnection.HTTP_OK)

 46        {

 47           return;

 48        }

 49  

 50        // Read server response

 51  

 52        InputStream instream = connection.getInputStream();

 53        Scanner in = new Scanner(instream);

 54  

 55        while (in.hasNextLine())

 56        {

 57           String input = in.nextLine();

 58           System.out.println(input);

 59        }

 60     }

 61  }