带有JavaFX MediaPlayer的小程序：无法创建MediaPlayer

我正在用JavaFXMediaPlayer编写一个（普通）小程序，在实例化MediaPlayer对象时出错。 我的第一个尝试是使用AccessController创建媒体对象，然后创建MediaPlayer

Media media = AccessController.doPrivileged(new ProxyNewMedia(path));
MediaPlayer player = new MediaPlayer(media);

这样做会得到以下异常：

Exception in thread "JavaFX Application Thread" MediaException: UNKNOWN : com.sun.media.jfxmedia.MediaException: Could not create player! : com.sun.media.jfxmedia.MediaException: Could not create player!
    at javafx.scene.media.MediaException.exceptionToMediaException(Unknown Source)
    at javafx.scene.media.MediaPlayer.init(Unknown Source)
    at javafx.scene.media.MediaPlayer.<init>(Unknown Source)
    at player.Player.start(Player.java:51)
    at gui.listener.recording.ListenerOpenPlayer$1.run(ListenerOpenPlayer.java:55)
    at com.sun.javafx.application.PlatformImpl$6$1.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$6$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl$6.run(Unknown Source)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(Unknown Source)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.access$300(Unknown Source)
    at com.sun.glass.ui.win.WinApplication$4$1.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: com.sun.media.jfxmedia.MediaException: Could not create player!
    at com.sun.media.jfxmediaimpl.NativeMediaManager.getPlayer(Unknown Source)
    at com.sun.media.jfxmedia.MediaManager.getPlayer(Unknown Source) 

提前谢谢

Exception in thread "JavaFX Application Thread" java.lang.NoClassDefFoundError: Could not initialize class com.sun.javafx.css.parser.CSSParser
at com.sun.javafx.css.StyleManager$CacheContainer.getInlineStyleSelector(Unknown Source)
    at com.sun.javafx.css.StyleManager$CacheContainer.access$1000(Unknown Source)
    at com.sun.javafx.css.StyleManager$Cache.getStyleMap(Unknown Source)
    at com.sun.javafx.css.StyleManager$Cache.access$800(Unknown Source)
    at com.sun.javafx.css.StyleManager.findMatchingStyles(Unknown Source)
    at javafx.scene.CssStyleHelper.createStyleHelper(Unknown Source)
    at javafx.scene.Node.impl_processCSS(Unknown Source)
    at javafx.scene.Parent.impl_processCSS(Unknown Source)
    at javafx.scene.Node.processCSS(Unknown Source)
    at javafx.scene.Scene.doCSSPass(Unknown Source)
    at javafx.scene.Scene.access$3500(Unknown Source)
    at javafx.scene.Scene$ScenePulseListener.pulse(Unknown Source)
    at com.sun.javafx.tk.Toolkit$3.run(Unknown Source)
    at com.sun.javafx.tk.Toolkit$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.Toolkit.runPulse(Unknown Source)
    at com.sun.javafx.tk.Toolkit.firePulse(Unknown Source)
    at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(Unknown Source)
    at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(Unknown Source)
    at com.sun.javafx.tk.quantum.QuantumToolkit$13.run(Unknown Source)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(Unknown Source)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.access$300(Unknown Source)
    at com.sun.glass.ui.win.WinApplication$4$1.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)