403 error in accessing an URL but works fine in browsers

Question

String url = "http://maps.googleapis.com/maps/api/directions/xml?origin=Chicago,IL&destination=Los+Angeles,CA&waypoints=Joplin,MO|Oklahoma+City,OK&sensor=false";

        URL google = new URL(url);
        HttpURLConnection con = (HttpURLConnection) google.openConnection();

and I use BufferedReader to print the content I get 403 error

The same URL works fine in the browser. Could any one suggest.

Answer 1

The reason it works in a browser but not in java code is that the browser adds some HTTP headers which you lack in your Java code, and the server requires those headers. I've been in the same situation - and the URL worked both in Chrome and the Chrome plugin "Simple REST Client", yet didn't work in Java. Adding this line before the getInputStream() solved the problem:

                connection.addRequestProperty("User-Agent", "Mozilla/4.0");

..even though I have never used Mozilla. Your situation might require a different header. It might be related to cookies ... I was getting text in the error stream advising me to enable cookies.

Note that you might get more information by looking at the error text. Here's my code:

        try {
            HttpURLConnection connection = ((HttpURLConnection)url.openConnection());
            connection.addRequestProperty("User-Agent", "Mozilla/4.0");
            InputStream input;
            if (connection.getResponseCode() == 200)  // this must be called before 'getErrorStream()' works
                input = connection.getInputStream();
            else input = connection.getErrorStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(input));
            String msg;
            while ((msg =reader.readLine()) != null)
                System.out.println(msg);
        } catch (IOException e) {
            System.err.println(e);
        }

Answer 2

HTTP 403 is a Forbidden status code. You would have to read the HttpURLConnection.getErrorStream() to see the response from the server (which can tell you why you have been given a HTTP 403), if any.