import java.io.InputStream; import java.io.IOException; import java.io.OutputStream; import java.io.PrintWriter; import java.net.HttpURLConnection; import java.net.URL; import java.net.URLConnection; import java.util.Scanner; /** This program demonstrates how to use an URL connection to communicate with a web server. Supply the URL on the command-line, for example java URLGet http://horstmann.com/index.html */ public class URLGet { public static void main(String[] args) throws IOException { // Get command-line arguments String urlString; if (args.length == 1) urlString = args[0]; else { urlString = "http://horstmann.com/"; System.out.println("Using " + urlString); } // Open connection URL u = new URL(urlString); URLConnection connection = u.openConnection(); // Check if response code is HTTP_OK (200) HttpURLConnection httpConnection = (HttpURLConnection) connection; int code = httpConnection.getResponseCode(); String message = httpConnection.getResponseMessage(); System.out.println(code + " " + message); if (code != HttpURLConnection.HTTP_OK) return; // Read server response InputStream instream = connection.getInputStream(); Scanner in = new Scanner(instream); while (in.hasNextLine()) { String input = in.nextLine(); System.out.println(input); } } }