HttpURLConnection and Redirects

[Andy Wilson]

I have an app that executes a Get method to a web server via HttpURLConnection. It works fine on the test server, but fails on the live server. Investigation shows that the live server is doing a rediect (status 302 gets returned). How do I get HttpURLConnection to follow the redirect: I've tried setting the instanceFollowRedirects to true, to no avail.

Code snippet is:

URL url = new URL("<<....>>");

HttpURLConnection c = (HttpURLConnection) url.openConnection();
c.setRequestMethod("GET");
c.setDoOutput(true);
c.setInstanceFollowRedirects(true);
BufferedReader in = new BufferedReader(new InputStreamReader(c.getInputStream()));

.....

I'm sure that this must be a common issue, but can't find any obvious solutions.

Cheers,
Andy Wilson

[Andy Wilson]

OK - first I don't think that I should be setting connection parameters after it's been opened! Even so, the follow redirects seems to default to true, so why doesn't it work? I know that the rediect doesn't require further intervention because I can use the Firefox poster utility to quite happily hit the URL.

[Aneesh Vijendran]

Hi,


You don't need to travel this far to do this simple stuff. I would ask you to have a look into Apache HttpClient:

A Sample Snippet:

 

HttpClient client = new HttpClient();

    // Create a method instance.
    GetMethod method = new GetMethod(url);
    
    // Provide custom retry handler is necessary
    method.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, 
    		new DefaultHttpMethodRetryHandler(3, false));

    try {
      // Execute the method.
      int statusCode = client.executeMethod(method);

      if (statusCode != HttpStatus.SC_OK) {
        System.err.println("Method failed: " + method.getStatusLine());
      }

      // Read the response body.
      byte[] responseBody = method.getResponseBody();

http://hc.apache.org/httpclient-3.x/features.html

Cheers
Aneesh

[Henry Wong]

Andy Wilson wrote:Even so, the follow redirects seems to default to true, so why doesn't it work?

Yeah, that doesn't make sense. The follow redirect is default to true, and should not need to be set. And I am assuming that you are not using a socket factory that clear it either.

Henry

[Andy Wilson]

No I'm clearing it (I've tested it to make sure that it's true).