/**发送post请求的方法

		 * @param params 请求参数的键-值对.

		 * @param url

		 * @param encoding

		 * @param setTimeout 标识是否设置连接超时.

		 * @param connectionTimeout 如果设置连接超时,连接超时时间.

		 * @return

		 * @throws MalformedURLException

		 * @throws IOException

		 * @throws JSONException

		 * @throws ParseException

		 */

		private boolean postSend(final Map<String, String> params,

				final String url, final String encoding, boolean setTimeout, final int connectionTimeout)

				throws MalformedURLException, IOException, JSONException,

				ParseException {

			// 封装请求参数的键值对.

			List<BasicNameValuePair> pairs = new ArrayList<BasicNameValuePair>();

			for (Entry<String, String> param : params.entrySet()) {

				pairs.add(new BasicNameValuePair(param.getKey(), param

						.getValue()));

			}

			// 封装请求参数的实体.

			UrlEncodedFormEntity entity = new UrlEncodedFormEntity(pairs,

					encoding);

			// 使用post请求.

			HttpPost post = new HttpPost(url);

			post.setEntity(entity);

			// 使用DefaultHttpClient指定请求,以获取响应信息.

			DefaultHttpClient client = new DefaultHttpClient();

			//设置连接超时.

			if(setTimeout) {

				final HttpParams httpParameters = client.getParams();

				HttpConnectionParams.setConnectionTimeout(httpParameters, connectionTimeout);

			}

			HttpResponse response = client.execute(post);

			BufferedReader reader = new BufferedReader(new InputStreamReader(

					response.getEntity().getContent(), encoding));

			// 使用线程安全的StringBuffer.

			StringBuffer buffer = new StringBuffer();

			String ln = null;

			while ((ln = reader.readLine()) != null)

				buffer.append(ln).append(System.getProperty("line.separator"));	//根据操作系统平台换行.

			// 传递json到Service处理.

			final String rawJsonStr = buffer.toString();

			//test only:

//			Log.i("sysout", rawJsonStr);

			resultAQIDays = convertJsonToAQIDayList(rawJsonStr);

			return response.getStatusLine().getStatusCode() == 200; // 等于200表示发送成功.

		}