代码如下：

// SoundApplet.java
import javax.swing.*;
import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class SoundApplet extends JApplet
                         implements ActionListener,
                                    ItemListener {
    AppletSoundList soundList;
    String auFile = "sound\\spacemusic.au";
    String aiffFile = "sound\\flute+hrn+mrmba.aif";
    String midiFile = "sound\\trippygaia1.mid";
    String rmfFile = "sound\\jungle.rmf";
    String wavFile = "sound\\bottle-open.wav";
    String chosenFile;
    AudioClip onceClip, loopClip;
    JComboBox formats;
    JButton playButton, loopButton, stopButton;
    boolean looping = false;

    public void init() {
        String [] fileTypes = {auFile,
                               aiffFile,
                               midiFile,
                               rmfFile,
                               wavFile};
        formats = new JComboBox(fileTypes);
        formats.setSelectedIndex(0);
        // 获得选中的声音文件名
        chosenFile = (String)formats.getSelectedItem();
        formats.addItemListener(this);

playButton = new JButton("Play");
playButton.addActionListener(this);

loopButton = new JButton("Loop");
loopButton.addActionListener(this);