How to Fetch a URL with HTTP Basic Authentication in Java?

How can I fetch a URL using HTTP Basic Authentication in Java?

String url = "http://example.com/api/resource"; URL obj = new URL(url);
HttpURLConnection con = (HttpURLConnection) obj.openConnection();

String user = "username";
String password = "password";
String encoded = Base64.getEncoder().encodeToString((user + ":" + password).getBytes(StandardCharsets.UTF_8));
con.setRequestProperty("Authorization", "Basic " + encoded);

Fetching a URL with HTTP Basic Authentication in Java can be accomplished using either the built-in `HttpURLConnection` class or third-party libraries like Apache HttpClient. This process involves encoding your credentials and adding them to the request headers.

import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Base64;
import java.nio.charset.StandardCharsets;

public class BasicAuthExample {
    public static void main(String[] args) {
        try {
            String url = "http://example.com/api/resource";
            URL obj = new URL(url);
            HttpURLConnection con = (HttpURLConnection) obj.openConnection();

            String user = "username";
            String password = "password";
            String encoded = Base64.getEncoder().encodeToString((user + ":" + password).getBytes(StandardCharsets.UTF_8));
            con.setRequestProperty("Authorization", "Basic " + encoded);

            int responseCode = con.getResponseCode();
            System.out.println("Response Code: " + responseCode);
            // Additional code to read the response... 
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Causes

• Incorrect URL format
• Invalid credentials
• Network issues preventing connection
• Missing required headers in the request

Solutions

• Ensure the URL is correctly formatted and accessible
• Double-check username and password for accuracy
• Check network settings and firewall configurations
• Include necessary HTTP headers in your request

Mistake: Not encoding credentials properly.

Solution: Always use `Base64` encoding to format the username and password correctly before sending.

Mistake: Using an incorrect URL.

Solution: Verify the URL and ensure that it points to a valid endpoint that requires authentication.

Mistake: Neglecting to check HTTP response codes.

Solution: Always check the response code to ensure the request was successful.