本文共 5019 字，大约阅读时间需要 16 分钟。

原理介绍

AIO，在NIO的基础上引入了异步通道的概念，并提供了异步文件和异步套接字通道的实现，从而在真正意义上实现了异步非阻塞，这是在jdk1.7及以后才有的。

AIO不需要通过类似NIO的多路复用器对注册的通道进行轮训操作，即可实现异步读写，从而简化了NIO的编程模型。也可以称为NIO2.0.这种模式才是真正的异步非阻塞模型。

AsynchonousServerSocketChannel

AsynchonousSocketChannel

代码演示 

代码：

import java.net.InetSocketAddress;import java.nio.channels.AsynchronousChannelGroup;import java.nio.channels.AsynchronousServerSocketChannel;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;public class Server {	//线程池	private ExecutorService executorService;	//线程组	private AsynchronousChannelGroup threadGroup;	//服务器通道	public AsynchronousServerSocketChannel assc;		public Server(int port){		try {			//创建一个缓存池			executorService = Executors.newCachedThreadPool();			//创建线程组			threadGroup = AsynchronousChannelGroup.withCachedThreadPool(executorService, 1);			//创建服务器通道			assc = AsynchronousServerSocketChannel.open(threadGroup);			//进行绑定			assc.bind(new InetSocketAddress(port));						System.out.println("server start , port : " + port);			//进行阻塞			assc.accept(this, new ServerCompletionHandler());			//一直阻塞 不让服务器停止			Thread.sleep(Integer.MAX_VALUE);					} catch (Exception e) {			e.printStackTrace();		}	}		public static void main(String[] args) {		Server server = new Server(8765);	}	}

import java.nio.ByteBuffer;import java.nio.channels.AsynchronousSocketChannel;import java.nio.channels.CompletionHandler;import java.util.concurrent.ExecutionException;public class ServerCompletionHandler implements CompletionHandler
   
     {	@Override	public void completed(AsynchronousSocketChannel asc, Server attachment) {		//当有下一个客户端接入的时候 直接调用Server的accept方法，这样反复执行下去，保证多个客户端都可以阻塞		attachment.assc.accept(attachment, this);		read(asc);	}	private void read(final AsynchronousSocketChannel asc) {		//读取数据		ByteBuffer buf = ByteBuffer.allocate(1024);		asc.read(buf, buf, new CompletionHandler
    
     () {			@Override			public void completed(Integer resultSize, ByteBuffer attachment) {				//进行读取之后,重置标识位				attachment.flip();				//获得读取的字节数				System.out.println("Server -> " + "收到客户端的数据长度为:" + resultSize);				//获取读取的数据				String resultData = new String(attachment.array()).trim();				System.out.println("Server -> " + "收到客户端的数据信息为:" + resultData);				String response = "服务器响应, 收到了客户端发来的数据: " + resultData;				write(asc, response);			}			@Override			public void failed(Throwable exc, ByteBuffer attachment) {				exc.printStackTrace();			}		});	}		private void write(AsynchronousSocketChannel asc, String response) {		try {			ByteBuffer buf = ByteBuffer.allocate(1024);			buf.put(response.getBytes());			buf.flip();			asc.write(buf).get();		} catch (InterruptedException e) {			e.printStackTrace();		} catch (ExecutionException e) {			e.printStackTrace();		}	}		@Override	public void failed(Throwable exc, Server attachment) {		exc.printStackTrace();	}}
    
   

import java.io.UnsupportedEncodingException;import java.net.InetSocketAddress;import java.nio.ByteBuffer;import java.nio.channels.AsynchronousSocketChannel;import java.util.concurrent.ExecutionException;public class Client implements Runnable{	private AsynchronousSocketChannel asc ;		public Client() throws Exception {		asc = AsynchronousSocketChannel.open();	}		public void connect(){		asc.connect(new InetSocketAddress("127.0.0.1", 8765));	}		public void write(String request){		try {			asc.write(ByteBuffer.wrap(request.getBytes())).get();			read();		} catch (Exception e) {			e.printStackTrace();		}	}	private void read() {		ByteBuffer buf = ByteBuffer.allocate(1024);		try {			asc.read(buf).get();			buf.flip();			byte[] respByte = new byte[buf.remaining()];			buf.get(respByte);			System.out.println(new String(respByte,"utf-8").trim());		} catch (InterruptedException e) {			e.printStackTrace();		} catch (ExecutionException e) {			e.printStackTrace();		} catch (UnsupportedEncodingException e) {			e.printStackTrace();		}	}		@Override	public void run() {		while(true){					}	}		public static void main(String[] args) throws Exception {		Client c1 = new Client();		c1.connect();				Client c2 = new Client();		c2.connect();				Client c3 = new Client();		c3.connect();				new Thread(c1, "c1").start();		new Thread(c2, "c2").start();		new Thread(c3, "c3").start();				Thread.sleep(1000);				c1.write("c1 aaa");		c2.write("c2 bbbb");		c3.write("c3 ccccc");	}	}

打印：

server端：

server start , port : 8765Server -> 收到客户端的数据长度为:6Server -> 收到客户端的数据信息为:c1 aaaServer -> 收到客户端的数据长度为:7Server -> 收到客户端的数据信息为:c2 bbbbServer -> 收到客户端的数据长度为:8Server -> 收到客户端的数据信息为:c3 ccccc

client端：

服务器响应, 收到了客户端发来的数据: c1 aaa服务器响应, 收到了客户端发来的数据: c2 bbbb服务器响应, 收到了客户端发来的数据: c3 ccccc

简单解读：

对于ServerCompletionHandler的Completed和failed方法的场景分别是，当服务器端接入了客户端channel后，就会调用complete方法，参数为(AsynchronousSocketChannel asc, Server attachment），就是一个客户端的channel和服务器端实例。

需要注意：

@Override	public void completed(AsynchronousSocketChannel asc, Server attachment) {		//当有下一个客户端接入的时候 直接调用Server的accept方法，这样反复执行下去，保证多个客户端都可以阻塞		attachment.assc.accept(attachment, this);		read(asc);	}

一定要先调用attachment.assc.accept(attachment, this);这个异步方法，保证后来的客户端可以正常接入。

异步方法：

转载地址：https://jeffsheng.blog.csdn.net/article/details/80736603 如侵犯您的版权，请留言回复原文章的地址，我们会给您删除此文章，给您带来不便请您谅解！