Connecting to the Network via HttpURLConnection

Connecting to the Network

Note that to perform the network operations, your application manifest must include the following permissions.

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

Most network-connected Android apps use HTTP to send and receive. Android includes two HTTP clients: HttpURLConnection and Apache HttpClient. And it is recommend using HttpURLConnection for applications targeted at Gingerbread and higher.

Check the Network Connection

Before your app attempts to connect to the network, it should check to see whether a network connection is available using getActiveNetworkInfo() and isConnected().

	public static boolean isNetworkAvailable(Context context) {
		ConnectivityManager manager = (ConnectivityManager) context
				.getSystemService(Context.CONNECTIVITY_SERVICE);
		NetworkInfo info = manager.getActiveNetworkInfo();
		if (info != null && info.isConnected()) {
			return true;
		}
		return false;
	}

Network operations can involve unpredictable delays. To prevent this from causing a poor user experience, always perform network operations on a separate thread from the UI. The AsyncTask provides one of the simplest ways to fire off a new task from the UI thread.

	private class DownloadTask extends AsyncTask<String, Void, String> {

		private String downloadUrl(String path) {
			try {
				URL url = new URL(path);

				HttpURLConnection connection = ((HttpURLConnection) url
						.openConnection());
				connection.setReadTimeout(10 * 1000);
				connection.setConnectTimeout(5 * 1000);
				connection.setRequestMethod("GET");
				connection.connect();

				if (connection.getResponseCode() == 200) {
					InputStream inputStream = connection.getInputStream();
					BufferedInputStream bis = new BufferedInputStream(inputStream);
					byte[] buffer = new byte[1024];
					int length = bis.read(buffer);
					return new String(buffer, 0, length);
				}
			} catch (MalformedURLException e) {
				e.printStackTrace();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return null;
		}
		
		@Override
		protected String doInBackground(String... params) {
			return downloadUrl(params[0]);
		}

		@Override
		protected void onPostExecute(String result) {
			Log.i("tag", result);
		}
	}

Connecting to the Network via HttpURLConnection

原文：http://blog.csdn.net/userqiaohaibin/article/details/45075367