高级套接字编程-服务器到客户端额外数据传输问题

这里有一个服务器和一个客户机。通过可选择的信道保持通信。 服务器---

  SelectionKey selectKey = channel.register(this.selector,

        SelectionKey.OP_ACCEPT);

while (selectKey.selector().select() > 0) {

    Set<SelectionKey> selectedKeys = this.selector.selectedKeys();

    Iterator<SelectionKey> iterator = selectedKeys.iterator();

    while (iterator.hasNext()) {

        SelectionKey key = iterator.next();

        iterator.remove();

        if (key.isAcceptable()) {

            ServerSocketChannel nextChannel = (ServerSocketChannel) key

                        .channel();
            SocketChannel newChannel = nextChannel.accept();

            newChannel.configureBlocking(false);

            if (!newChannel.isRegistered()) {

                SelectionKey selectionKey = newChannel.register(

                     this.selector, SelectionKey.OP_READ

                | SelectionKey.OP_WRITE);

                selectionKey.attach(newChannel);

            }

        } else if (key.isWritable()) {

             SocketChannel attachment1 = (SocketChannel)key.attachment();
             ByteBuffer writeBuffer = ByteBuffer.wrap("Hello".getBytes());

                attachment1.write(writeBuffer);

                System.out.print("Written");
            }
         }
      } 

客户:

   InetSocketAddress isa = new InetSocketAddress(InetAddress
            .getLocalHost(), 4444);
    SocketChannel sc = null;

    try {

        while (true) {

            Thread.sleep(10000);
            sc = SocketChannel.open();
            sc.connect(isa);
            ByteBuffer byteBuffer = ByteBuffer.allocate(BUFSIZE);
            int nbytes = sc.read(byteBuffer);
            byteBuffer.flip();
            dbuf.flip();
            CharBuffer cb = decoder.decode(byteBuffer);
            System.out.println(isa + " : " + cb);

        }

问题是每次客户机读取的数据都达到了客户机的最大缓冲区限制,而不是发送的数据限制。