使用java写一段nio的通信代码

以下是一个简单的NIO通信代码示例，它能够建立一个服务器并接收客户端的连接请求，在客户端和服务器之间发送简单的消息。

服务器端代码：

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class NIOServer {

    private static final int PORT = 8080;

    public static void main(String[] args) throws IOException {
        ExecutorService executor = Executors.newFixedThreadPool(10);
        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
        serverSocketChannel.socket().bind(new InetSocketAddress(PORT));
        serverSocketChannel.configureBlocking(false);
        System.out.println("Server started on port " + PORT);

        while (true) {
            SocketChannel socketChannel = serverSocketChannel.accept();
            if (socketChannel != null) {
                System.out.println("Client connected: " + socketChannel.getRemoteAddress());
                executor.submit(new ClientHandler(socketChannel));
            }
        }
    }

    private static class ClientHandler implements Runnable {
        private final SocketChannel socketChannel;

        private ClientHandler(SocketChannel socketChannel) {
            this.socketChannel = socketChannel;
        }

        @Override
        public void run() {
            ByteBuffer buffer = ByteBuffer.allocate(1024);
            try {
                while (socketChannel.read(buffer) > 0) {
                    buffer.flip();
                    byte[] bytes = new byte[buffer.remaining()];
                    buffer.get(bytes);
                    System.out.println("Received message from " + socketChannel.getRemoteAddress() + ": " + new String(bytes));
                    buffer.clear();
                }
            } catch (IOException e) {
                System.err.println("Error reading message from " + socketChannel.getRemoteAddress() + ": " + e.getMessage());
            } finally {
                try {
                    socketChannel.close();
                } catch (IOException e) {
                    System.err.println("Error closing connection to " + socketChannel.getRemoteAddress() + ": " + e.getMessage());
                }
            }
        }
    }
}

客户端代码：

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

public class NIOClient {

    private static final String HOST = "localhost";
    private static final int PORT = 8080;

    public static void main(String[] args) throws IOException {
        SocketChannel socketChannel = SocketChannel.open(new InetSocketAddress(HOST, PORT));
        System.out.println("Connected to server on " + socketChannel.getRemoteAddress());

        String message = "Hello, server!";
        ByteBuffer buffer = ByteBuffer.wrap(message.getBytes());
        socketChannel.write(buffer);
        System.out.println("Sent message to server: " + message);

        buffer.clear();
        int bytesRead = socketChannel.read(buffer);
        while (bytesRead > 0) {
            buffer.flip();
            byte[] bytes = new byte[buffer.remaining()];
            buffer.get(bytes);
            System.out.println("Received response from server: " + new String(bytes));
            buffer.clear();
            bytesRead = socketChannel.read(buffer);
        }
        socketChannel.close();
    }
}