How to retrieve redirect url from http server.?

Question

I am getting 200 as a response code instead of 3xx when I perform HTTP post request, even though web page gets redirected automatically. I tried this, but dosen't work. My code:

HttpURLConnection con = getMultipartHttpURLConnection(
        formParameter.getServerUrl(), boundary);
setRequestHeaders(con);
String urlParameters = getParameter(formParameter.getForm());
// Send post request
con.setDoOutput(true);
DataOutputStream wr = new DataOutputStream(con.getOutputStream());
wr.writeBytes(urlParameters);
wr.flush();
wr.close();
responseCode = con.getResponseCode();
String header = con.getHeaderField("Location");

Edit:

By some research I find out that if server is configured to redirect to https:// enabled url, then I am getting 3xx as response code, otherwise not. Example given in the link above does the same.

Christian Hujer · Accepted Answer · 2014-12-03 04:15:40Z

1

That's because HttpURLConnection is smart and handles the redirection internally. The 200 response code is the response code of the new location to which the redirection happened.

The only way that I am aware of how you could retrieve the redirection URL is to use setFollowRedirects(false) and follow the redirection manually.

See the following example:

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;

public class GetRedirectURL {
    public static void main(final String... args) throws IOException {
        final URL url = new URL("http://www.google.com/");
        //HttpURLConnection.setFollowRedirects(false);
        final HttpURLConnection con = (HttpURLConnection) url.openConnection();
        //con.setInstanceFollowRedirects(false);
        final int responseCode = con.getResponseCode();
        final String location = con.getHeaderField("Location");
        System.err.format("%d%n%s%n", responseCode, location);
    }
}

If you leave this code unmodified, it will print 200 null. If you uncomment any of the lines controlling the redirection behavior, the output changes to `200 http://www.google...' .

It's important that modifying the redirection settings is done before the statemachine of the HttpURLConnection instance is, by method calls that read from the response, to send the request.

edited Dec 3, 2014 at 4:15

answered Dec 2, 2014 at 10:38

Christian Hujer

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7 Comments

Madhav Bhattarai Over a year ago

Ok,but how to read the redirection url and how to check whether redirection url exists or not.

Christian Hujer Over a year ago

See the edit that I just made, I forgot the original question because it wasn't repeated in the text.

Madhav Bhattarai Over a year ago

i tried both connection.setInstanceFollowRedirects(true); HttpURLConnection.setFollowRedirects(true); and both dosen't helped. Please check the link that i edited in question.

Christian Hujer Over a year ago

Did you use true or false as value? It needs to be false, but in your comment you write true.

Madhav Bhattarai Over a year ago

I tried using both true/false but that too dosen't make the difference.

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