Jsoup Check Redirect URL

In this article, we will show you how to use Jsoup to check if an URL is going to redirect.

1. URL Redirection

Normally, a redirect URL will return an HTTP code of 301 or 307, and the target URL will be existed in the response header “location” field.

Review a sample of HTTP Response header

{ 
	Location=http://mkyong.com
	Server=GSE, 
	Cache-Control=no-cache, 
	no-store, 
	max-age=0, 
	must-revalidate

2. Jsoup Example

2.1 By default, Jsoup will follow the redirect recursively and display the final URL.

package com.mkyong.crawler;
import java.io.IOException;
import org.jsoup.Connection.Response;
import org.jsoup.Jsoup;
public class RedirectExample {
	public static void main(String[] args) throws IOException {
		String url = "http://goo.gl/fb/gyBkwR";
		Response response = Jsoup.connect(url).execute();
		System.out.println(response.statusCode() + " : " + response.url());

Output

200 : http://www.mkyong.com/mongodb/mongodb-remove-a-field-from-array-documents/

2.2 To test the URL redirection, set followRedirects to false.

	Response response = Jsoup.connect(url).followRedirects(false).execute();
	System.out.println(response.statusCode() + " : " + response.url());
	//check if URL is redirect? 
	System.out.println("Is URL going to redirect : " + response.hasHeader("location"));
	System.out.println("Target : " + response.header("location"));

Output

301 : http://goo.gl/fb/gyBkwR
Is URL going to redirect : true
Target : http://feeds.feedburner.com/~r/FeedForMkyong/~3/D_6Jqi4trqo/...

3. Jsoup Example, Again

3.1 This example will print out the redirect URLs recursively.

package com.mkyong.crawler;
import java.io.IOException;
import org.jsoup.Connection.Response;
import org.jsoup.Jsoup;
public class RedirectExample {
	public static void main(String[] args) throws IOException {
		String url = "http://goo.gl/fb/gyBkwR";
		RedirectExample obj = new RedirectExample();
		obj.crawl(url);
	private void crawl(String url) throws IOException {
		Response response = Jsoup.connect(url).followRedirects(false).execute();
		System.out.println(response.statusCode() + " : " + url);
		if (response.hasHeader("location")) {
			String redirectUrl = response.header("location");
			crawl(redirectUrl);

Output

301 : http://goo.gl/fb/gyBkwR
301 : http://feeds.feedburner.com/~r/FeedForMkyong/~3/D_6Jqi4trqo/...
200 : http://www.mkyong.com/mongodb/mongodb-remove-a-field-from-array-documents/

References

1. Wikipedia : URL Redirection