Java nio实现socket通信遇到的有关问题

import java.io.IOException;import java.net.InetSocketAddress;import java.nio.ByteBuffer;import java.nio.channels.SelectionKey;import java.nio.channels.Selector;import java.nio.channels.ServerSocketChannel;import java.nio.channels.SocketChannel;import java.util.Calendar;import java.util.Iterator;public class TestServer {    public static void main(String[] args) {        new EchoServer(1982);    }}class EchoServer implements Runnable {    //要监听的端口号    private int port;    //生成一个信号监视器    private Selector s;    //读缓冲区    private ByteBuffer r_bBuf = ByteBuffer.allocate(1024);        public EchoServer(int port) {        this.port = port;        try {            s = Selector.open();        } catch (IOException e) {            e.printStackTrace();        }        new Thread(this).start();    }    @Override    public void run() {        try {            //生成一个ServerScoket通道的实例对象，用于侦听可能发生的IO事件            ServerSocketChannel ssc = ServerSocketChannel.open();            //将该通道设置为异步方式            ssc.configureBlocking(false);            //绑定到一个指定的端口            ssc.socket().bind(new InetSocketAddress(port));            //注册特定类型的事件到信号监视器上            ssc.register(s, SelectionKey.OP_ACCEPT);            System.out.println("The server has been launched...");            while(true) {                //将会阻塞执行，直到有事件发生                System.out.println("监听新事件...");                s.select();                Iterator<SelectionKey> it = s.selectedKeys().iterator();                while(it.hasNext()) {                    SelectionKey key = it.next();                    //key定义了四种不同形式的操作                    switch(key.readyOps()) {                    case SelectionKey.OP_ACCEPT :                        dealwithAccept(key);                        break;                    case SelectionKey.OP_CONNECT :                        break;                    case SelectionKey.OP_READ :                        break;                    case SelectionKey.OP_WRITE :                        dealwithRead(key);                        break;                    }                    //处理结束后移除当前事件，以免重复处理                    it.remove();                }            }        } catch (IOException e) {            e.printStackTrace();        }    }    //处理接收连接的事件    private void dealwithAccept(SelectionKey key) {        try {            System.out.println("deal with new accept...");            ServerSocketChannel server = (ServerSocketChannel)key.channel();            SocketChannel sc = server.accept();            sc.configureBlocking(false);            //注册读事件            sc.register(s, SelectionKey.OP_WRITE);            System.out.println("deal with new accept2...");        } catch (IOException e) {            e.printStackTrace();        }    }    //处理客户端发来的消息，处理读事件    private void dealwithRead(SelectionKey key) {        try {            SocketChannel sc = (SocketChannel)key.channel();            System.out.println("读入数据");            r_bBuf.clear();            System.out.println(r_bBuf.position());            sc.write(r_bBuf);            System.out.println(r_bBuf.position());            r_bBuf.flip();            System.out.println(r_bBuf.asCharBuffer().toString());            r_bBuf.clear();            System.out.println("处理完毕...");            try {                Thread.currentThread().sleep(10000000);            } catch (InterruptedException e) {                e.printStackTrace();            }        } catch (IOException e) {            e.printStackTrace();        }    }        private String getCurrentTime() {        return Calendar.getInstance().toString();    }}