AIO主要API

• AsynchronousServerSocketChannel

       服务端Socket通道类，负责服务端Socket的创建和监听；

用法示例：

final AsynchronousServerSocketChannel listener =
      AsynchronousServerSocketChannel.open().bind(new InetSocketAddress(5000));

  listener.accept(null, new CompletionHandler() {
      public void completed(AsynchronousSocketChannel ch, Void att) {
          // accept the next connection
          listener.accept(null, this);

          // handle this connection
          handle(ch);
      }
      public void failed(Throwable exc, Void att) {
          ...
      }
  }); 

• AsynchronousSocketChannel

       客户端Socket通道类，负责客户端消息读写；

//AsynchronousSocketChannel open有两个重载方法

//打开异步套接字通道。
public static AsynchronousSocketChannel open(AsynchronousChannelGroup group)
                                      throws IOException

public static AsynchronousSocketChannel open()
                                      throws IOException

• CompletionHandler

       消息处理回调接口，是一个负责消费异步IO操作结果的消息处理器；