Springboot的tcp服务端搭建

@Slf4j
public class NIOServer {
    private InetAddress addr;
    private int port;
    private Selector selector;

    private static int BUFF_SIZE = 1024;

    public NIOServer(InetAddress addr, int port) throws IOException {
        this.addr = addr;
        this.port = port;
        startServer();
    }

    private void startServer() throws IOException {
        // 获得selector及通道(socketChannel)
        this.selector = Selector.open();
        ServerSocketChannel serverChannel = ServerSocketChannel.open();
        serverChannel.configureBlocking(false);

        // 绑定地址及端口
        InetSocketAddress listenAddr = new InetSocketAddress(this.addr, this.port);
        serverChannel.socket().bind(listenAddr);
        serverChannel.register(this.selector, SelectionKey.OP_ACCEPT);

        log.info("NIOServer运行中...按下Ctrl-C停止服务");

        while (true) {
            log.info("服务器等待新的连接和selector选择…");
            this.selector.select();

            // 选择key工作
            Iterator keys = this.selector.selectedKeys().iterator();
            while (keys.hasNext()) {
                SelectionKey key = (SelectionKey) keys.next();

                // 防止出现重复的key，处理完需及时移除
                keys.remove();

                //无效直接跳过
                if (!key.isValid()) {
                    continue;
                }
                if (key.isAcceptable()) {
                    this.accept(key);
                } else if (key.isReadable()) {
                    this.read(key);
                } else if (key.isWritable()) {
                    this.write(key);
                } else if (key.isConnectable()) {
                    this.connect(key);
                }
            }
        }
    }

    private void connect(SelectionKey key) throws IOException {
        SocketChannel channel = (SocketChannel) key.channel();
        if (channel.finishConnect()) {
            // 成功
            log.info("成功连接了");
        } else {
            // 失败
            log.info("失败连接");
        }
    }

    private void accept(SelectionKey key) throws IOException {
        ServerSocketChannel serverChannel = (ServerSocketChannel) key.channel();
        SocketChannel channel = serverChannel.accept();
        channel.configureBlocking(false);
        channel.register(this.selector, SelectionKey.OP_READ);

        Socket socket = channel.socket();
        SocketAddress remoteAddr = socket.getRemoteSocketAddress();
        log.info("连接到: "+   remoteAddr);
    }

    private void read(SelectionKey key) throws IOException {
        SocketChannel channel = (SocketChannel) key.channel();

        ByteBuffer buffer = ByteBuffer.allocate(BUFF_SIZE);
        int numRead = channel.read(buffer);
        if (numRead == -1) {
            log.info("关闭客户端连接: " +  channel.socket().getRemoteSocketAddress());
            channel.close();
            return;
        }
        String msg = new String(buffer.array()).trim();
        log.info("得到了: "+msg);

        // 回复客户端
        String reMsg = msg +  " 你好，这是BIOServer给你的回复消息:" +  System.currentTimeMillis();
        channel.write(ByteBuffer.wrap(reMsg.getBytes()));
    }

    private void write(SelectionKey key) throws IOException {
        ByteBuffer byteBuffer = ByteBuffer.allocate(BUFF_SIZE);
        byteBuffer.flip();
        SocketChannel clientChannel = (SocketChannel) key.channel();
        while (byteBuffer.hasRemaining()) {
            clientChannel.write(byteBuffer);
        }
        byteBuffer.compact();
    }
}