网络编程之每天学习一点点[day5]-----aio编程

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：

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 : 8765
Server -> 收到客户端的数据长度为:6
Server -> 收到客户端的数据信息为:c1 aaa
Server -> 收到客户端的数据长度为:7
Server -> 收到客户端的数据信息为:c2 bbbb
Server -> 收到客户端的数据长度为:8
Server -> 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Complent和fail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：