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JAVA POST request and then redirect to it?

What I need to do is send POST request to specific URL with two parameters and when the request is sent, I need to redirect user to that link so that he would be able to access functionality.
So far, what I have managed to do from various examples is this:
private void postRemoteAdvisoryLink() throws IOException {
URL obj = new URL(KdrmApplicationContext.getRemoteAdvisoryUrlPath());
HttpURLConnection con = (HttpURLConnection) obj.openConnection();
con.setConnectTimeout(60000);
con.setRequestMethod("POST");
con.setRequestProperty("User-Agent", "Mozilla/5.0");
con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");
// For post only - start
con.setDoOutput(true);
OutputStream os = con.getOutputStream();
os.write(("?auth=ssor&TransportKey=" + ssorTransportKey).getBytes());
os.flush();
os.close();
int responseCode = con.getResponseCode();
}
The problem is that now I get connection time out when trying to execute OutputStream os = con.getOutputStream(); line. Also, I still have no idea how to redirect user when request is completed.
Any ideas?

Using the basic Java URL classes would require you to manually handle the details of HTTP protocol - it's better to use libraries like Apache Http Components, as they deal with the underlying protocols for you. Some examples including POST requests can be found on their website.
Given the original question, the Timeout is likely related to host not responding or your Java application being unable to connect to given URL (due to no proxy configuration for example).
If you want to redirect a request based on the answer, you need to check the response headers and http status - if the status is 302, then there should be a header called Location, which will contain the URL you should make another request to.
Before getting an OutputStream, also make sure to set the Content-Length header (and ideally the Content-Type header as well).

HttpUrlConnection reading chunked response

I'm working on a project where i have to use HttpUrlConnection (Android~) for reading the input stream.
It turns out that when i'm reading the input stream the data is malformed and has a bigger size from the original content (which is sent by the server). Now, the server response header contains both "Content-Length" and "Transfer-Encoding: chunked", which from what i know is an issue as both of them shouldn't coexist.
Aside from that the input stream received from HttpUrlConnection contains all body content (with chunks offset informations).
I have two questions:
Shouldn't the HttpUrlConnection handle chunked data?
How to get the data from input stream without chunked informations?

The HttpUrlConnection should be handling chunked data, you're correct. The fact that you're seeing these headers at all means they're probably being malformed somewhere, and something has already sent either a \n\n or \r\n\r\n, so the HttpUrlConnection views it as part of the actual transmission.
If you WANT to be getting the raw data, use a socket and connect to the url on the correct port (probably 80, 443 for ssl)
EDIT: java.net.URLConnection states under the connect() method
Interact with the resource; query header fields and contents.
This shows that a URLConnection, prior to reading anything in from any sort of provided reader, queries the header information. Pardon me for not including this the first time.

Does HttpURLConnection support compression/decompression out of the box?

I'm using the HttpURLConnection to make some GET request and fetch pages. I'd like to request gzipped responses but I haven't found any information whether HttpURLConnection support Gzip.
Do i need to simply add the header Accept-Encoidng: gzip to the request or is there something else I need to do in order to handle gzipped responses?

No, the HttpURLConnection does not "handle" compression out of the box. It simply streams the request and response using HTTP. You will need to handle the response compression if it is utilized, which you can find out by checking the response header, for example
Content-Encoding: gzip
The encoding type may be something other than gzip, too. Like you mentioned, you need to set your request header, stating you support compression.

Setting content length of an HTTP POST request

I am trying to make a Http POST request using apache HTTP client. I am trying to copy contents of an HTTP POST request (received at my application) to another HTTP POST request (initiated from my application to another URL). Code is shown below:
httpPost = new HttpPost(inputURL);
// copy headers
for (Enumeration<String> e = request.getHeaderNames(); e.hasMoreElements();) {
String headerName = e.nextElement().toString();
httpPost.setHeader(headerName, request.getHeader(headerName));
}
BufferedInputStream clientToProxyBuf = new BufferedInputStream(request.getInputStream());
BasicHttpEntity basicHttpEntity = new BasicHttpEntity();
basicHttpEntity.setContent(clientToProxyBuf);
basicHttpEntity.setContentLength(clientToProxyBuf.available());
httpPost.setEntity(basicHttpEntity);
HttpResponse responseFromWeb = httpclient.execute(httpPost);
Basically, I am trying to implement a proxy application which will get a url as parameter, froward the request to the URL and then serve pages etc in custom look and feel.
Here request is HttpServletRequest. I am facing problem in setting content length. Through debugging I found out that clientToProxyBuf.available() is not giving me correct length of input stream and I am getting Http error 400 IE and Error 354 (net::ERR_CONTENT_LENGTH_MISMATCH): The server unexpectedly closed the connection in chrome.
Am I doing it wrong? Is there any other way to achieve it?

The available() function doesn't provide the actual length of the content of the stream, rather
Returns the number of bytes that can be read from this input stream without blocking. (From javadoc)
I would suggest you to first read the whole content from the stream, and then set that to the content, rather than passing the stream object. That way, you will also have the actual length of the content.

It was rather simple and very obvious. I just needed to get content length from header as:
basicHttpEntity.setContentLength(Integer.parseInt(request.getHeader("Content-Length")));

How do I differentiate between request and response in an HTTPURLConnection?

Hi I need to evaluate if a server supports gzip compression.
Therefore I want to set gzip as Accept-Encoding in my request and evaluate if the response of the server containts "Content-Encoding: gzip".
However I am not quite clear on how to do this with HTTPURLConnection. Especially when to query my Connection object about the response. I currently do:
HttpURLConnection con = (HttpURLConnection) feedurl.openConnection();
con.setRequestProperty("Accept-Encoding", "gzip");
System.out.println("Current Accept-Encoding: "+con.getRequestProperty("Accept-Encoding"));
//check the response for the content-size
float feedsize = con.getContentLength()/1024f;
//the server uses transfer-encoding=chunked and does not specify
//a content length
if(con.getContentLength()==-1)
{
//count the content size manually
CountingInputStream counter = new CountingInputStream(con.getInputStream());
while(counter.read()!=-1)
{}
feedsize=counter.getCount()/1024f;
}
con.disconnect();

Have a look at this OReilly article. It illustrates how to generate the request, and how to interrogate the response and then create the appropriate stream (normal or gzipped) dependent on what's being returned.