如何读取HTTP POST请求返回的XML？

Question

NOT a duplicate of my other question.

I am sending a POST request like this:

        String urlParameters = "a=b&c=d";
        String request = "http://www.example.com/";

        URL url = new URL(request);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();      
        connection.setDoOutput(true);
        connection.setDoInput(true);
        connection.setInstanceFollowRedirects(false); 
        connection.setRequestMethod("POST");
        connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); 
        connection.setRequestProperty("charset", "utf-8");
        connection.setRequestProperty("Content-Length", "" + Integer.toString(urlParameters.getBytes().length));
        connection.setUseCaches(false);

        DataOutputStream wr = new DataOutputStream(connection.getOutputStream());
        wr.writeBytes(urlParameters);
        wr.flush();
        wr.close();
        connection.disconnect();

How can I read the xml response returned from a HTTP POST request? Particularly, I want to save the response file as a .xml file, and then read it. For my usual GET requests, I use this:

    SAXBuilder builder = new SAXBuilder();
    URL website = new URL(urlToParse);
    ReadableByteChannel rbc = Channels.newChannel(website.openStream());
    FileOutputStream fos = new FileOutputStream("request.xml");
    fos.getChannel().transferFrom(rbc, 0, 1 << 24);
    fos.close();
    // Do the work

Addendum : I'm using the following code and it works just fine. However, it neglects any spacing and new lines and treats the complete XML contents as a single line. How do I fix it?

    InputStream is = connection.getInputStream();
    BufferedReader br = new BufferedReader(new InputStreamReader(is));
    StringBuilder sb1 = new StringBuilder();
    String line;
    while ((line = br.readLine()) != null) {
        sb1.append(line);
    }
    FileOutputStream f = new FileOutputStream("request.xml");
    f.write(sb1.toString().getBytes());
    f.close();
    br.close();

Answer 1

don't use Readers and readLine() with xml data. use InputStreams and byte[] s.

Answer 2

Thanks to Pangea, I modified his code and this now works:

    TransformerFactory transFactory = TransformerFactory.newInstance();
    Transformer t= transFactory.newTransformer();
    t.setOutputProperty(OutputKeys.METHOD, "xml");
    t.setOutputProperty(OutputKeys.INDENT,"yes");                
    Source input = new StreamSource(is);
    Result output = new StreamResult(new FileOutputStream("request.xml"));
    transFactory.newTransformer().transform(input, output);