我的第一个长程序，虽然是直接抄了书上，可是还是出现了两次拼写错误，最终还是找到异常的答案，改过来了。

一开始是下面红字部分，那个数组，少打了一个字，导致·原来16字长的数组变成了15字长，在后面，instruments数组赋值给其他数组的时候，出现了数组溢出的错误。


  1 import java.awt.*;
import javax.swing.*;
import javax.sound.midi.*;
import java.util.*;
import java.awt.event.*;

public class BeatBox {

    JPanel mainPanel;
    ArrayList<JCheckBox> checkboxList;
    Sequencer sequencer;
    Sequence sequence;
    Track track;
    JFrame theFrame;
    
    String[] instrumentNames={"Bass Drum","Closed Hi-Hat",
            "Open Hi-Hat","Acoustic Snare","Crash Cymbal",
            "Hand Clap","High Tom","Hi Bongo","Maracas","Whistle",
            "Low Conga","Cowbell","Vibraslap","Low-mid Tom","High Agogo","Open Hi Conga"};//乐器的名称，以String的array维护。
    int[] instruments={35,42,46,38,49,39,50,60,70,72,64,56,58,47,67,63};//实际的乐器关键字，例如说35是bass,42是Closed Hi-Hat。
    
    public static void main(String[] args){
        new BeatBox().buildGUI();
    }
    public void buildGUI(){
        theFrame=new JFrame("CyberBeatBox");
        theFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        BorderLayout layout=new BorderLayout();
        JPanel background=new JPanel(layout);
        background.setBorder(BorderFactory.createEmptyBorder(10,10,10,10));//设置面板上摆设组件时的空白边缘。
        
        checkboxList=new ArrayList<JCheckBox>();
        Box buttonBox=new Box(BoxLayout.Y_AXIS);//设置buttonBox沿着Y轴摆放。
        
        JButton start=new JButton("Start");
        start.addActionListener(new MyStartListener());
        buttonBox.add(start);
        
        JButton stop=new JButton("Stop");
        stop.addActionListener(new MyStopListener());
        buttonBox.add(stop);
        
        JButton upTempo=new JButton("Tempo Up");
        upTempo.addActionListener(new MyUpTempoListener());
        buttonBox.add(upTempo);
        
        JButton downTempo=new JButton("Tempo Down");
        downTempo.addActionListener(new MyDownTempoListener());
        buttonBox.add(downTempo);
        
        Box nameBox=new Box(BoxLayout.Y_AXIS);
        for (int i=0;i<16;i++){
            nameBox.add(new Label(instrumentNames[i]));
        }
            
            background.add(BorderLayout.EAST,buttonBox);
            background.add(BorderLayout.WEST,nameBox);
            
            theFrame.getContentPane().add(background);
            
            GridLayout grid=new GridLayout(16,16);
            grid.setVgap(1);
            grid.setHgap(2);
            mainPanel=new JPanel(grid);
            background.add(BorderLayout.CENTER,mainPanel);
            
            for(int i=0;i<256;i++){
                JCheckBox c=new JCheckBox();
                c.setSelected(false);
                checkboxList.add(c);
                mainPanel.add(c);
                }//创建checkbox组，设定成未勾选的为false并加到ArrayList和面板上。

            setUpMidi();
            
            theFrame.setBounds(50,50,300,300);
            theFrame.pack();
            theFrame.setVisible(true);
        }//关闭方法
        
    public void setUpMidi() {
        // TODO Auto-generated method stub
        try{
            sequencer=MidiSystem.getSequencer();
            sequencer.open();
            sequence=new Sequence(Sequence.PPQ,4);
            track=sequence.createTrack();
            sequencer.setTempoInBPM(120);
        }catch(Exception e){e.printStackTrace();}
    }//关闭方法
    public void buildTrackAndStart(){
        int[] trackList=null;
        
        sequence.deleteTrack(track);
        track=sequence.createTrack();
        
        for(int i=0;i<16;i++){
            trackList=new int[16];
            
            int key=instruments[i];
            
            for(int j=0;j<16;j++){
                JCheckBox jc=(JCheckBox) checkboxList.get(j+(16*i));
                if(jc.isSelected()){
                    trackList[j]=key;
                }else{
                    trackList[j]=0;
                }
            }//关闭内部循环
            
            makeTracks(trackList);
            track.add(makeEvent(176,1,127,0,16));
        }//关闭外部循环
        
        track.add(makeEvent(192,9,1,0,15));
        try{
            
            sequencer.setSequence(sequence);
            sequencer.setLoopCount(sequencer.LOOP_CONTINUOUSLY);
            sequencer.start();
            sequencer.setTempoInBPM(120);
        }catch(Exception e){e.printStackTrace();}
    }//关闭buildTrackAndStart方法。
    public class MyStartListener implements ActionListener{
        public void actionPerformed(ActionEvent a){
            //buildTrackAndStart();
            buildTrackAndStart();
        }
    }//关闭内部类
    public class MyStopListener implements ActionListener{
        public void actionPerformed(ActionEvent a){
            sequencer.stop();
        }    
    }//关闭内部类
    public class MyUpTempoListener implements ActionListener{
        public void actionPerformed(ActionEvent a){
            float tempoFactor=sequencer.getTempoFactor();
            sequencer.setTempoFactor((float)(tempoFactor*1.03));
        }    
    }//关闭内部类
    public class MyDownTempoListener implements ActionListener{
        public void actionPerformed(ActionEvent a){
            float tempoFactor=sequencer.getTempoFactor();
            sequencer.setTempoFactor((float)(tempoFactor*.97));
        }    
    }//关闭内部类
    
    
    public void makeTracks(int[] list){
        for(int i=0;i<16;i++){
            int key=list[i];
            
            if(key!=0){
                track.add(makeEvent(144,9,key,100,i));
                track.add(makeEvent(128,9,key,100,i+1));
            }
        }
    }
    public MidiEvent makeEvent(int comd,int chan,int one,int two,int tick){
        MidiEvent event=null;
        try{
            ShortMessage a=new ShortMessage();
            a.setMessage(comd,chan,one,two);
            event=new MidiEvent(a,tick);
        }catch(Exception e){e.printStackTrace();}
        return event;
    }
}

下面这个报错，就是运行时候，出现了“数组越界问题。”：。。。。。java.lang.ArrayIndexOutOfBoundsException....翻译成汉语，还真是数组越界。。。不难嘛~~~