windows-media-player - JavaFx-MediaView 不显示视频

Question

selectFile.setOnAction(new EventHandler<ActionEvent>() {

    @Override
    public void handle(ActionEvent event) {

        FileChooser chooser = new FileChooser(); 
        chooser.getExtensionFilters().add("select (*mp4)", "*.mp4");
        
        try {
            fileToPlay = fileChooser.showOpenDialog(null);
            Media m = new Media(fileToPlay.toURI().toString());
            MediaPlayer mp = new MediaPlayer(m);
            mediaPlayer.setMediaPlayer(mp);
            mp.play();

        } catch (IOException ex) {
            System.out.println(ex.getMessage());
        }
    }

});