How to use HttpURLConnection POST data to web server?

public static String get_PostPageSourceByURLConnection(String urlRequestString,String PostParamString)    
 {         String WholeString = "";         
           try {             
                URL url = new URL(urlRequestString);             
               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(PostParamString.getBytes().length));             connection.setUseCaches (false);
            DataOutputStream writer = new DataOutputStream(connection.getOutputStream ());
            writer.writeBytes(PostParamString);
            writer.flush();
           
            String line;
            StringBuffer strBuilder = new StringBuffer();
            BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            while ((line = reader.readLine()) != null)
            {
                strBuilder = strBuilder.append(line);
                strBuilder = strBuilder.append("\n\n\n");
            }
            WholeString = strBuilder.toString();
           
            writer.close();
            reader.close();
           
            connection.disconnect();
        }
        catch (Exception ex)
        {
            String s = ex.toString();
            s = s.trim();
        }
        finally
        {
            return WholeString;
        }
       
    }