程序代码：

package AIO;

import import java.nio.ByteBuffer;
import java.nio.channels.AsynchronousChannelGroup;
import java.nio.channels.AsynchronousServerSocketChannel;
import java.nio.channels.AsynchronousSocketChannel;
import java.nio.import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class AIOServer 
{
    static final int PORT = 30000 ;
    final static String UTF_8 = "utf-8" ;
    static List<AsynchronousSocketChannel> channelList = new ArrayList<>();
    public void startListen() throws InterruptedException , Exception
    {
        //创建一个线程池
        ExecutorService executor = Executors.newFixedThreadPool(20);
        //以指定线程池来创建一个AsynchronousChannelGroup
        AsynchronousChannelGroup channelGroup = AsynchronousChannelGroup.withThreadPool(executor);
        //以指定线程池来创建一个AsynchronousServerSocketChannel
        AsynchronousServerSocketChannel serverChannel = AsynchronousServerSocketChannel.open(channelGroup).bind(new InetSocketAddress(PORT));
        serverChannel.accept(null, new AcceptHandler(serverChannel));
    }
    public static void main(String args[]) throws Exception
    {
        AIOServer server = new AIOServer();
        server.startListen();
    }
}
//实现自己的CompletionHandler类
class AcceptHandler implements CompletionHandler<AsynchronousSocketChannel,Object>
{
    private AsynchronousServerSocketChannel serverChannel ;
    public AcceptHandler(AsynchronousServerSocketChannel sc)
    {
        this.serverChannel = sc ;
    }
    //定义一个ByteBuffer准备读取数据
    ByteBuffer buff = ByteBuffer.allocate(1024);
    //当实际IO操作完成时触发该方法
    @Override
    public void completed(final AsynchronousSocketChannel sc , Object attachment)
    {
        AIOServer.channelList.add(sc);
        serverChannel.accept(null , this );
        sc.read(buff, null, new CompletionHandler<Integer,object>()
                {
            public void completed (Integer result , Object attachment)
            {
                buff.flip();
                //将buff中的内容转换为字符串
                String content = StandardCharsets.UTF_8.decode(buff).toString();
                //遍历每个Channel，将收到的信息写入各Chaneel中
                for(AsynchronousSocketChannel c : AIOServer.channelList)
                {
                    try
                    {
                        c.write(ByteBuffer.wrap(content.getBytes(AIOServer.UTF_8))).get();
                    }
                    catch(Exception ex )
                    {
                        ex.printStackTrace();
                    }
                }
                buff.clear();
                sc.read(buff,null,this);
            }
            @Override
            public void failed(Throwable ex ,Object attachment)
            {
                System.out.println("读取数据失败："+ex);
                //从该Channel中读取数据失败，就将该Channel删除
                AIOServer.channelList.remove(sc);
            }
                });
        }
    @Override
    public void failed(Throwable ex , Object attachment )
    {
        System.out.println("连接失败："+ex);
    }
}