编写程序，在Applet中使用下拉框显示音乐文件的名字，在程序中使用AudioChip类控制播放的音乐文件，使用“播放”、“连续”、“停止”控制按钮选择播放音乐的状态。

本文链接：https://blog.youkuaiyun.com/jianstyle/article/details/6046128

本文介绍了一个使用Java Applet实现的声音播放器程序。该程序能够加载并播放不同格式的声音文件，包括AU、AIFF、MIDI、RMF和WAV格式。用户可以通过界面上的按钮选择文件类型、播放、循环播放或停止播放声音。

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//fiute+hrn+mrmba.aif";
String midiFile = "sound//trippygaial.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);
    chosenFile = (String)formats.getSelectedItem();
    formats.addItemListener(this);
    playButton=new JButton("播放");
    playButton.addActionListener(this);
    loopButton=new JButton("连续");
    loopButton.addActionListener(this);
    stopButton=new JButton("停止");
    stopButton.addActionListener(this);
    stopButton.setEnabled(false);

    JPanel controlPanel=new JPanel();
    controlPanel.add(formats);
    controlPanel.add(playButton);
    controlPanel.add(loopButton);
    controlPanel.add(stopButton);
    getContentPane().add(controlPanel);
    startLoadingSounds();
    }

    public void itemStateChanged(ItemEvent e)
    {
    chosenFile=(String)formats.getSelectedItem();
    soundList.startLoading(chosenFile);
    }
    void startLoadingSounds()
    {
    soundList=new AppletSoundList(this, getCodeBase());
    soundList.startLoading(auFile);
    soundList.startLoading(aiffFile);
    soundList.startLoading(midiFile);
    soundList.startLoading(rmfFile);
    soundList.startLoading(wavFile);
    }
    public void stop()
    {
    onceClip.stop();
    if(looping)
    {
      loopClip.stop();
    }
    }
    public void start()
    {
    if(looping)
    {
      loopClip.loop();
    }
    }
    public void actionPerformed(ActionEvent event)
    {
    Object source=event.getSource();
    if(source==playButton)
    {
      onceClip=soundList.getClip(chosenFile);
      onceClip.play();
      stopButton.setEnabled(true);
      showStatus("Playing sound" +chosenFile+".");
      if(onceClip==null)
      {
       showStatus("Sound"+chosenFile+"not loaded yet.");
      }
         return;
        }
        if(source==loopButton)
        {
        loopClip=soundList.getClip(chosenFile);
        looping=true;
        loopClip.loop();
        loopButton.setEnabled(false);
        stopButton.setEnabled(true);
        showStatus("Playing sound"+chosenFile+"continuously.");
        if(loopClip==null)
        {
      showStatus("sound"+chosenFile+"not loaded yet.");
        }
        return;
         }
         if(source==stopButton)
         {
    if(looping)
    {
      looping=false;
      loopClip.stop();
      loopButton.setEnabled(true);
    }
    else if(onceClip!=null)
    {
      onceClip.stop();
    }
    stopButton.setEnabled(false);
    showStatus("Stopped playing"+chosenFile+".");
    return;
         }
    }
}

import javax.swing.*;
import java.applet.*;
import java.net.URL;
class AppletSoundLoader extends Thread
{
JApplet applet;
AppletSoundList soundList;
URL baseURL;
String relativeURL;
public AppletSoundLoader(JApplet applet,AppletSoundList soundList,URL baseURL,String relativeURL)
{
  this.applet=applet;
  this.soundList=soundList;
  this.baseURL=baseURL;
  this.relativeURL=relativeURL;
  setPriority(MIN_PRIORITY);
  start();
}
public void run()
{
  AudioClip audioClip=applet.getAudioClip(baseURL,relativeURL);
  soundList.putClip(audioClip,relativeURL);
}
}

import javax.swing.*;
import java.applet.*;
import java.net.URL;
class AppletSoundList extends java.util.Hashtable
{
JApplet applet;
URL baseURL;
public AppletSoundList(JApplet applet,URL baseURL)
{
  this.applet=applet;
  this.baseURL=baseURL;
}
public void startLoading(String relativeURl)
{
  new AppletSoundLoader(applet,this,baseURL,relativeURl);
}
public AudioClip getClip(String relativeURL)
{
  return(AudioClip)get(relativeURL);
}
public void putClip(AudioClip clip,String relativeURL)
{
  put(relativeURL,clip);
}
}