NTLM Authentication from Java

Connecting to a web page from Java is very easy. You use the HttpURLConnection method like so:

HttpURLConnection conn = (HttpURLConnection) url.openConnection();
       conn.setDoOutput(true);
       conn.setDoInput(true);
       conn.setRequestMethod("GET");

       // Get the response
       BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
       String line;
       while ((line = rd.readLine()) != null) {
           System.out.println(line);
       }
       rd.close();

This works, but what if you need to access a password protected web page? Then you need to define an "Authenticator."

static class MyAuthenticator extends Authenticator {
       public PasswordAuthentication getPasswordAuthentication() {
           System.out.println("trying to authenticate");
          return new PasswordAuthentication("username", "password".toCharArray());
       }
    }

Now before you call HttpUrlConnection you set the authenticator. The full code is displayed below:

import java.io.*;
import java.net.*;
class Notify {
    static class MyAuthenticator extends Authenticator {
       public PasswordAuthentication getPasswordAuthentication() {
           System.out.println("trying to authenticate");
          return new PasswordAuthentication("username", "password".toCharArray());
       }
    }
public  static void main(String argv[]) throws Exception {
       // Construct data
       Authenticator.setDefault(new MyAuthenticator());
       URL url = new URL("<ntlm protected="" url="">");
       HttpURLConnection conn = (HttpURLConnection) url.openConnection();
       conn.setDoOutput(true);
       conn.setDoInput(true);
       conn.setRequestMethod("GET");

       // Get the response
       BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
       String line;
       while ((line = rd.readLine()) != null) {
           System.out.println(line);
       }
       rd.close();

 }
}

Hope that helps...