public String post(String url, Map<String, String> postData) {
            HttpPost httpPost = new HttpPost(url);
            List<NameValuePair> params = new ArrayList<NameValuePair>();

            if (postData != null) {
                for (String key : postData.keySet()) {
                    params.add(new BasicNameValuePair(key, postData.get(key)));
                }
            }
            try {
                httpPost.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
                String content = httpclient.execute(httpPost,
                        new BasicResponseHandler());
                return content;
            } catch (Exception e) {
                e.printStackTrace();
            }
            return null;
        }