java scoket aIO 通信

AsynchronousServerSocketChannel

assc.accept(this, new ServerCompletionHandler()); 第一个参数是服务器的处理类，第二个参数当服务接受到客户端的连接之后，用来处理客户端的连接

这里accept并不是一直阻塞的，会继续向下面执行，为了保证服务器端程序一直运行存在，所以这里使用了

//进行阻塞。第一个参数可以是null
assc.accept(this, new ServerCompletionHandler());
//一直阻塞 不让服务器停止
Thread.sleep(Integer.MAX_VALUE);

this就是当前的服务器端的实例对象，ServerCompletionHandler用来处理客户端请求数据的，必须实现implements CompletionHandler<AsynchronousSocketChannel, Server>

第一个参数AsynchronousSocketChannel就是当前服务器端的Channel通道对象，第二参数和assc.accept(this, new ServerCompletionHandler());中的第一个参数必须一一对应

实现CompletionHandler接口必须实现下面的两个方法

completed

failed

@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);
}

attachment就是传递进来的服务器对象，attachment.assc就是Server类的channel对象，然后在调用channel对象对象的accept对象,就和在server端调用assc.accept(this, new ServerCompletionHandler());一样

在 completed函数中进行递归调用assc.accept(this, new ServerCompletionHandler())

接下来就可以读取客户端连接的数据了read(asc);

来一个客户端就调用一次assc.accept(this, new ServerCompletionHandler())，所以在在 completed函数中进行递归调用assc.accept(this, new ServerCompletionHandler())进行递归调用

我们来看下客户端服务器的代码：

package bhz.aio;

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,1表示初始化一个线程池
            threadGroup = AsynchronousChannelGroup.withCachedThreadPool(executorService, 1);
            //创建服务器通道
            assc = AsynchronousServerSocketChannel.open(threadGroup);
            //进行绑定，这里就没有nio的seletor操作
            assc.bind(new InetSocketAddress(port));
            System.out.println("server start , port : " + port);
            //进行阻塞。第一个参数可以是null
            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);
    }

}

package bhz.aio;

import java.nio.ByteBuffer;
import java.nio.channels.AsynchronousSocketChannel;
import java.nio.channels.CompletionHandler;
import java.util.concurrent.ExecutionException;

public class ServerCompletionHandler implements CompletionHandler<AsynchronousSocketChannel, Server> {

    @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);
    }

    //AsynchronousSocketChannel客户端的通道
    private void read(final AsynchronousSocketChannel asc) {
        //读取数据，异步的读取数据
        ByteBuffer buf = ByteBuffer.allocate(1024);
        asc.read(buf, buf, new CompletionHandler<Integer, ByteBuffer>() {
            @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();
    }

}

package bhz.aio;

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");
    }

}

程序运行的结果是：

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