一个URL问题~~~

import java.net.*;
import java.applet.*;
import java.awt.event.*;
import java.awt.Container;
import java.awt.FlowLayout;
import javax.swing.*;
public class Sound extends JFrame implements ActionListener{
private JButton playMusic=new JButton("play");
    private JButton loopMusic=new JButton("loop");
    private JButton stopMusic=new JButton("stop");
    private JButton playSound=new JButton("play s");
    private JButton stopSound=new JButton("stop s");
    private AudioClip music =null,sound=null;
    public Sound()
    {super("Sound test");
         //下面的URL定位，我的声音文件在  //F:\eclipse\eclipse\workspace\Sharkgame\soundtest\Audio
    try
{String separator=System.getProperty("file.separator");//此处file该是哪个？
String preface="file:"+System.getProperty("soundtest.dir")//此处的file又是哪个？+separator+"Autio"+separator;
music=Applet.newAudioClip(new URL(preface+"s.wav"));
sound=Applet.newAudioClip(new URL(preface+"v.wav"));
}
    catch(MalformedURLException murle)
{System.err.println("Error loading files"+murle);}
    Container c=getContentPane();
    c.setLayout(new FlowLayout());
    c.add(playMusic);playMusic.addActionListener(this);
    c.add(loopMusic);loopMusic.addActionListener(this);
    c.add(stopMusic);stopMusic.addActionListener(this);
    c.add(playSound);playSound.addActionListener(this);
    c.add(stopSound);stopSound.addActionListener(this);
    validate();pack();setVisible(true);
    }
    public void actionPerformed(ActionEvent e)
    {if(e.getSource()==playMusic)
     music.play();
    else if(e.getSource()==loopMusic)
     music.loop();
    else if(e.getSource()==stopMusic)
     music.stop();
    else if(e.getSource()==playSound)
     sound.play();
    else if(e.getSource()==stopSound)
     sound.stop();
    }
    public static void main(String args[])
    {Sound st=new Sound();}
}
我是菜鸟。。帮帮忙。。