Where is the bug?

Question

I�m trying to post two different messages to a server, using a same connection (keep-alive):
URL url = new URL("http://localhost:8080");
HttpURLConnection connection = url.openConnection();
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setUseCaches(false);
connection.setAllowUserInteraction(true);
// POST #1
connection.setRequestProperty( "Content-Type", ";application/x-www-form-urlencoded);
connection.connect();
DataOutputStream postStream = new DataOutputStream(connection.getOutputStream());
postStream.write("Hi server".getBytes());
postStream.flush();
postStream.close();
// Here I�m reading the server response...
connection.disconnect();
// POST #2
connection.setRequestProperty( "Content-Type", ";application/x-www-form-urlencoded);
connection.connect();
DataOutputStream postStream = new DataOutputStream(connection.getOutputStream());
postStream.write("It�s me again".getBytes());
postStream.flush();
postStream.close();
// Here I�m reading the server response...
connection.disconnect();The execution of the above code produce the following error:
java.net.ProtocolException: Cannot write output after reading input.Any tip?

Answer 1

You need to parse get the session id out of the cookie that is set back in the response headers. Then you need to send the session id back in the next request headers.
Like this:
      /* To get cookie. */
      HttpURLConnection huc= (HttpURLConnection) url.openConnection();
      InputStream is = huc.getInputStream();
      // Retrieve session ID from response.
      String cookieVal = hc.getHeaderField("Set-Cookie");
      String sessionId;
      if(cookieVal != null)
            sessionId = cookieVal.substring(0, cookieVal.indexOf(";"));
      /* To send cookie. */
      HttpURLConnection huc= (HttpURLConnection) url.openConnection();
      if(sessionId != null)
            huc.setRequestProperty("Cookie", sessionId);
      InputStream is = huc.getInputStream();
      ...Hope this helps.