Java를 사용하여 Websocket 파일 전송 기능을 개발하는 방법

@ServerEndpoint("/upload")
public class FileUploadServer {

    @OnOpen
    public void onOpen(Session session) {
        System.out.println("Client connected: " + session.getId());
    }

    @OnMessage
    public void onMessage(ByteBuffer byteBuffer, Session session) throws IOException {
        Path path = Paths.get("uploads", session.getId() + ".jpg");
        Files.write(path, byteBuffer.array());
        System.out.println("File uploaded: " + path.toString());
    }

    @OnClose
    public void onClose(Session session) {
        System.out.println("Client disconnected: " + session.getId());
    }

    @OnError
    public void onError(Throwable e) {
        e.printStackTrace();
    }
}

public class FileUploadClient extends Application {

    private static final String SERVER_URI = "ws://localhost:8080/upload";

    private WebSocketClient client;

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage primaryStage) {
        try {
            URI uri = new URI(SERVER_URI);
            client = new WebSocketClient(uri) {
                @Override
                public void onOpen(ServerHandshake handshakedata) {
                    System.out.println("Connected to server");
                }

                @Override
                public void onMessage(String message) {
                    System.out.println("Received message: " + message);
                }

                @Override
                public void onClose(int code, String reason, boolean remote) {
                    System.out.println("Disconnected from server");
                }

                @Override
                public void onError(Exception ex) {
                    ex.printStackTrace();
                }
            };
            client.connect();
        } catch (URISyntaxException e) {
            e.printStackTrace();
        }
    }

    public void uploadFile(Path path) throws IOException {
        byte[] bytes = Files.readAllBytes(path);
        client.send(bytes);
        System.out.println("File uploaded: " + path.toString());
    }
}