Java 非同步io式（AIO）

執行流程

AIO(proactor模型)：執行緒發起IO請求，立即返回；記憶體做好IO操作的準備之後，做IO操作，直到操作完成或者失敗，通過呼叫註冊的回撥函式通知執行緒做IO操作完成或者失敗。 非同步非阻塞，伺服器實現模式為一個有效請求一個執行緒，客戶端的I/O請求都是由OS先完成了再通知伺服器應用去啟動執行緒進行處理，

程式碼

1.server

public class Server {
    private static Charset charset = Charset.forName("utf-8");
    private static CharsetEncoder encoder =
 
 charset.newEncoder();

    public static void main(String[] args) throws Exception {
        AsynchronousChannelGroup group = AsynchronousChannelGroup.withThreadPool(Executors.newFixedThreadPool(4));
        AsynchronousServerSocketChannel server = AsynchronousServerSocketChannel.open(group).bind(new
 
 InetSocketAddress("0.0.0.0", 8013));
        server.accept(null, new CompletionHandler<AsynchronousSocketChannel, Void>() {
            @Override
            public void completed(AsynchronousSocketChannel result, Void attachment) {
                server.accept(null, this); // 接受下一個連線
                try
 
 {
                    String now = new Date().toString();
                    ByteBuffer buffer = encoder.encode(CharBuffer.wrap(now + "\r\n"));
                    //result.write(buffer, null, new CompletionHandler<Integer,Void>(){...}); //callback or
                    Future<Integer> f = result.write(buffer);
                    f.get();
                    System.out.println("sent to client: " + now);
                    result.close();
                } catch (IOException | InterruptedException | ExecutionException e) {
                    e.printStackTrace();
                }
            }
            @Override
            public void failed(Throwable exc, Void attachment) {
                exc.printStackTrace();
            }
        });
        group.awaitTermination(Long.MAX_VALUE, TimeUnit.SECONDS);
    }
}

2.client

public class Client {
    public static void main(String[] args) throws Exception {
        AsynchronousSocketChannel client = AsynchronousSocketChannel.open();
        Future<Void> future = client.connect(new InetSocketAddress("127.0.0.1", 8013));
        future.get();

        ByteBuffer buffer = ByteBuffer.allocate(100);
        client.read(buffer, null, new CompletionHandler<Integer, Void>() {
            @Override
            public void completed(Integer result, Void attachment) {
                System.out.println("client received: " + new String(buffer.array()));

            }
            @Override
            public void failed(Throwable exc, Void attachment) {
                exc.printStackTrace();
                try {
                    client.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }

            }
        });

        Thread.sleep(10000);
    }
}