Java基础知识强化之网络编程笔记24：Android网络通信之 AndroidAsync（基于nio的异步通信库）

1. AndroidAsync  

　　AndroidAsync 是一个基于nio的异步socket ，http（客户端服务器端），websocket，socket.io库，AndroidAsync 是一个底层的网络协议库，如果你想要一个容易使用，高级的，http请求库，请使用Ion（它是基于AndroidAsync 的），正常来说开发者更倾向于使用  Ion。

如果你需要一个未被封装的Android的raw Socket， HTTP client/server, WebSocket, and Socket.IO， AndroidAsync 正适合你。

2. AndroidAsync 的特性

• 基于NIO，一个线程，回调驱动，高效

•  所有的操作返回一个Future，而且可以取消

• All operations return a Future that can be cancelled

• Socket client + socket server

• HTTP client + server

• WebSocket client + server

• Socket.IO 客户端

3. AndroidAsync 的下载

<dependency>

    <groupId>com.koushikdutta.async</groupId>

    <artifactId>androidasync</artifactId>

    <version>(insert latest version)</version>

</dependency>

4. AndroidAsync 的使用

（1）下载一个字符串

 // url is the URL to download.
 AsyncHttpClient.getDefaultInstance().getString(url, new AsyncHttpClient.StringCallback() {
     // Callback is invoked with any exceptions/errors, and the result, if available.
     @Override
     public void onCompleted(Exception e, AsyncHttpResponse response, String result) {
         if (e != null) {
             e.printStackTrace();
             return;
         }
         System.out.println("I got a string: " + result);
     }
 });

（2）下载一个Json

 // url is the URL to download.
 AsyncHttpClient.getDefaultInstance().getJSONObject(url, new AsyncHttpClient.JSONObjectCallback() {
     // Callback is invoked with any exceptions/errors, and the result, if available.
     @Override
     public void onCompleted(Exception e, AsyncHttpResponse response, JSONObject result) {
         if (e != null) {
             e.printStackTrace();
             return;
         }
         System.out.println("I got a JSONObject: " + result);
     }
 });

（3）下载一个文件

 AsyncHttpClient.getDefaultInstance().getFile(url, filename, new AsyncHttpClient.FileCallback() {
     @Override
     public void onCompleted(Exception e, AsyncHttpResponse response, File result) {
         if (e != null) {
             e.printStackTrace();
             return;
         }
         System.out.println("my file is available at: " + result.getAbsolutePath());
     }
 });

（4）支持缓存

 // arguments are the http client, the directory to store cache files, and the size of the cache in bytes
 ResponseCacheMiddleware.addCache(AsyncHttpClient.getDefaultInstance(),
                                   getFileStreamPath("asynccache"),
                                   1024 * 1024 * 10);

（5）创建一个Socket

 AsyncHttpClient.getDefaultInstance().websocket(get, "my-protocol", new WebSocketConnectCallback() {
     @Override
     public void onCompleted(Exception ex, WebSocket webSocket) {
         if (ex != null) {
             ex.printStackTrace();
             return;
         }
         webSocket.send("a string");
         webSocket.send(new byte[10]);
         webSocket.setStringCallback(new StringCallback() {
             public void onStringAvailable(String s) {
                 System.out.println("I got a string: " + s);
             }
         });
         webSocket.setDataCallback(new DataCallback() {
             public void onDataAvailable(ByteBufferList byteBufferList) {
                 System.out.println("I got some bytes!");
                 // note that this data has been read
                 byteBufferList.recycle();
             }
         });
     }
 });

（6）支持socket io

 SocketIOClient.connect(AsyncHttpClient.getDefaultInstance(), "http://192.168.1.2:3000", new ConnectCallback() {
     @Override
     public void onConnectCompleted(Exception ex, SocketIOClient client) {
         if (ex != null) {
             ex.printStackTrace();
             return;
         }
         client.setStringCallback(new StringCallback() {
             @Override
             public void onString(String string) {
                 System.out.println(string);
             }
         });
         client.on("someEvent", new EventCallback() {
             @Override
             public void onEvent(JSONArray argument, Acknowledge acknowledge) {
                 System.out.println("args: " + arguments.toString());
             }
         });
         client.setJSONCallback(new JSONCallback() {
             @Override
             public void onJSON(JSONObject json) {
                 System.out.println("json: " + json.toString());
             }
         });
     }
 });

（7）提交表单

 AsyncHttpPost post = new AsyncHttpPost("http://myservercom/postform.html");
 MultipartFormDataBody body = new MultipartFormDataBody();
 body.addFilePart("my-file", new File("/path/to/file.txt");
 body.addStringPart("foo", "bar");
 post.setBody(body);
 AsyncHttpClient.getDefaultInstance().execute(post, new StringCallback() {
     @Override
     public void onCompleted(Exception e, AsyncHttpResponse source, String result) {
         if (e != null) {
             ex.printStackTrace();
             return;
         }
         System.out.println("Server says: " + result);
     }
 });

（8）创建一个http server

 AsyncHttpServer server = new AsyncHttpServer();
 List<WebSocket> _sockets = new ArrayList<WebSocket>();
 server.get("/", new HttpServerRequestCallback() {
     @Override
     public void onRequest(AsyncHttpServerRequest request, AsyncHttpServerResponse response) {
         response.send("Hello!!!");
     }
 });
 // listen on port 5000
 server.listen(5000);
 // browsing http://localhost:5000 will return Hello!!!

接着，创建一个websocket  server

 server.websocket("/live", new WebSocketRequestCallback() {
     @Override
     public void onConnected(final WebSocket webSocket, AsyncHttpServerRequest request) {
         _sockets.add(webSocket);
         //Use this to clean up any references to your websocket
         websocket.setClosedCallback(new CompletedCallback() {
             @Override
             public void onCompleted(Exception ex) {
                 try {
                     if (ex != null)
                         Log.e("WebSocket", "Error");
                 } finally {
                     _sockets.remove(webSocket);
                 }
             }
         });
         webSocket.setStringCallback(new StringCallback() {
             @Override
             public void onStringAvailable(String s) {
                 if ("Hello Server".equals(s))
                     webSocket.send("Welcome Client!");
             }
         });
     }
 });
 //..Sometime later, broadcast!
 for (WebSocket socket : _sockets)
     socket.send("Fireball!");

（9）支持Future

 Future<String> string = client.getString("http://foo.com/hello.txt");
 // this will block, and may also throw if there was an error!
 String value = string.get();

5. AndroidAsync的下载

开源地址：https://github.com/koush/AndroidAsync