学习nio通信的问题，伙伴们看下吧，感激不尽

server端和client端通信出现问题

运行结果及报错内容

package nio;

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.Iterator;

/**
 * @author: cqh
 * @date: 2022/8/14
 * @desc:
 **/
public class Server {
    public static void main(String[] args) {
        try {
            ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
            ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
            serverSocketChannel.bind(new InetSocketAddress("127.0.0.1", 9000));
            serverSocketChannel.configureBlocking(false);
            Selector selector = Selector.open();
            serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);

            while (true) {
                Iterator iterator = selector.selectedKeys().iterator();
                while (iterator.hasNext()) {
                    SelectionKey selectionKey = iterator.next();
                    if (selectionKey.isAcceptable()) {
                        SocketChannel socketChannel = serverSocketChannel.accept();
                        socketChannel.configureBlocking(false);
                        socketChannel.register(selector, SelectionKey.OP_READ);
                    } else if (selectionKey.isReadable()) {
                        int len = 0;
                        SocketChannel socketChannel = (SocketChannel) selectionKey.channel();
                        while ((len = socketChannel.read(byteBuffer)) > 0) {
                            byteBuffer.flip();
                            System.out.println(new String(byteBuffer.array(), 0, len));
                            byteBuffer.clear();
                        }
                    }
                    iterator.remove();
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

package nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;
import java.util.Scanner;

/**
 * @author: cqh
 * @date: 2022/8/14
 * @desc:
 **/
public class Client {
    public static void main(String[] args) {
        try {
            SocketChannel socketChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1", 9000));
            System.out.println(socketChannel.getRemoteAddress());
            if (socketChannel.isConnected()) {
                System.out.println("连接中");
            }
            socketChannel.configureBlocking(false);
            Scanner scanner = new Scanner(System.in);
            String msg = null;
            while ((msg = scanner.nextLine()) != null) {
                socketChannel.write(ByteBuffer.wrap(msg.getBytes()));
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}

伙伴们能帮忙看下，为什么这两段代码不能实现通信效果呢