我尝试制作一个随机歌曲播放器失败了

Question

我试图创建一个系统，在那里你点击按钮，它会播放五个可能的随机midi文件。它总是只播放第一首歌请帮忙。整数i是随机选择的，但由于我不知道的原因，URL不会从sus2更改，因此音频保持不变。

import java.net.URL;
import java.awt.event.*;
import javax.swing.ImageIcon;
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Option extends JFrame implements ActionListener{   

/**
 * 
 */
private static final long serialVersionUID = 1L;
URL image= this.getClass().getResource("/tick.png");
URL url = this.getClass().getResource("/sus.mid");
ImageIcon img = new ImageIcon(image);
JButton testBut = new JButton(img);
JPanel pnl = new JPanel();
java.applet.AudioClip audio = JApplet.newAudioClip(url);
public Option(){
    super("Swing Window");
    pnl.add(testBut);
    add(pnl);
    setSize( 500,350);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setVisible(true);
    testBut.addActionListener(this);


}
public void actionPerformed(ActionEvent event){
    if (event.getSource() == testBut) {
        int i = (int) Math.ceil(Math.random() * 5);
        switch(i){
        case 1: url = this.getClass().getResource("/sus.mid");
        case 2: url = this.getClass().getResource("/sus2.mid");
        case 3: url = this.getClass().getResource("/sus3.mid");
        case 4: url = this.getClass().getResource("/sus4.mid");
        case 5: url = this.getClass().getResource("/sus5.mid");
        System.out.println(i);
        }
        audio = JApplet.newAudioClip(url);
        audio.stop();
        audio.play();
    }
}
public static void main(String[] args){
Option gui = new Option();
}
}

Answer 1

您在每个case块之后都忘记了break指令：

case 1: 
    url = this.getClass().getResource("/sus.mid");
    break;
case 2: 
    url = this.getClass().getResource("/sus2.mid");
    break;
...