如何使用Java NIO实现一个高性能的Echo服务器？

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.*;
import java.net.InetSocketAddress;
import java.util.Iterator;
import java.util.Set;

public class EchoServer {
    public static void main(String[] args) {
        try {
            // 创建Selector和ServerSocketChannel
            Selector selector = Selector.open();
            ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
            serverSocketChannel.bind(new InetSocketAddress(8080));
            serverSocketChannel.configureBlocking(false);

            // 注册到Selector，关注OP_ACCEPT事件
            serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
            System.out.println("Server started on port 8080...");

            // 轮询处理事件
            while (true) {
                // 阻塞直到有事件就绪
                selector.select();

                // 获取所有已就绪的SelectionKey
                Set<SelectionKey> selectedKeys = selector.selectedKeys();
                Iterator<SelectionKey> iterator = selectedKeys.iterator();

                while (iterator.hasNext()) {
                    SelectionKey key = iterator.next();
                    iterator.remove();

                    if (key.isAcceptable()) {
                        // 处理连接请求
                        acceptConnection(serverSocketChannel, selector);
                    }

                    if (key.isReadable()) {
                        // 处理客户端发送的数据
                        handleClientRead(key);
                    }
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    // 处理新连接
    private static void acceptConnection(ServerSocketChannel serverSocketChannel, Selector selector) throws IOException {
        SocketChannel clientChannel = serverSocketChannel.accept();
        clientChannel.configureBlocking(false);

        // 注册到Selector，关注OP_READ事件
        clientChannel.register(selector, SelectionKey.OP_READ);
        System.out.println("New client connected: " + clientChannel.getRemoteAddress());
    }

    // 处理客户端读数据
    private static void handleClientRead(SelectionKey key) throws IOException {
        SocketChannel clientChannel = (SocketChannel) key.channel();
        ByteBuffer buffer = ByteBuffer.allocate(256);

        int bytesRead = clientChannel.read(buffer);
        if (bytesRead == -1) {
            // 客户端断开连接
            System.out.println("Client disconnected");
            clientChannel.close();
        } else {
            // 回显客户端发送的数据
            buffer.flip();
            clientChannel.write(buffer);
            System.out.println("Echoed back to client: " + new String(buffer.array(), 0, bytesRead));
        }
    }
}