我正在学习 java，据我所知，我想做的是一种罕见的情况。
我正在尝试使用 API (kindof) 随机生成音符。我希望它生成 20 次，所以我将它放在一个 for 循环中。我意识到我可以为此使用一个列表，我只是不知道如何实现它。我的问题是，当我尝试编译这段代码时，第一部分会运行。它让我做种子。但是在那之后它给了我
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 2
at co.kbcomp.music.Main.main(Main.java:64)
我能做些什么来防止这种情况发生？我知道我所做的是错误的。这么多我就不用说了。我想知道我哪里错了。
package co.kbcomp.music;
import java.util.*;
import org.jfugue.*;
import java.util.Scanner;
public class Main {
public static void main(String[] args){
Scanner in = new Scanner(System.in);
System.out.println("Please enter a number for the seed of the song");
long seed = in.nextLong();
Calendar cal = Calendar.getInstance();
Random rand;
//rand = new Random(cal.getTime());
rand = new Random(seed);
int NoteNumber = 0;
int NoteLength = 0;
int OctiveNumber = 0;
int ChordNumber = 0;
int InversionNumber = 0;
//int Duration = rand.nextInt(100 - 5) + 5;
//This keeps track of the iteration of the for loop.
String[] NN = { " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " "};
String[] NL = { " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " "};
String[] IN = { " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " "};
String[] CN = { " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " "};
String[] ON = { " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " "};
//This is what is being played
String[] note = { "A", "B", "C", "D", "E", "F", "G" };
String[] noteLength = {"", "w", "", "h", "", "q","", "i"};
String[] octive = { "","1","", "2", "", "3", "", "4", "", "5", "", "6", "", "7", "", "8", "", "9"};
String[] chord = { "", "maj", "", "min"};
String[] inversion = {"", "^", "", "^^", "", "^^^", "", "^^^^", "", "^^^^^"};
String[] key = {"",""};
String keys= " ";
String randstr = " ";
//this is the loop that defines the music legnth
for (int i = 0; i < 21; i++) {
NoteNumber = rand.nextInt(7);
NoteLength = rand.nextInt(8);
OctiveNumber = rand.nextInt(18);
ChordNumber = rand.nextInt(4);
InversionNumber = rand.nextInt(10);
NN[i] = note[NoteNumber]; // This randomly generates the note to be played.
NL[i] = noteLength[NoteLength]; // This randomly generates the length of the note.
ON[i] = octive[OctiveNumber]; // This defines the octive to be played in.
CN[i] = chord[ChordNumber]; // This is defines the major or the minor
IN[i] = inversion[InversionNumber]; // IN[i] = inversion[InversionNumber];
key[i] = NN[i] + NL[i] + ON[i] + CN[i] + IN[i];
//randstr = c[0] + " " + c[1] + " " + c[2] + " " + c[3] + " " + c[4] + " " + c[5] + " " + c[6] + " " + c[7] + " " + c[8] + " " + c[9] + " " + c[10] + " " + c[11] + " " + c[12] + " " + c[13] + " " + c[14] + " " + c[15] + " " + c[16];
keys = (key[0] + " " + key[1] + " " + key[2] + " " + key[3] + " " + key[4] + " " + key[5] + " " + key[6] + " " + key[7] + " " + key[8] + " " + key[9] + " " + key[10] + " " + key[11] + " " + key[12] + " " + key[13] + " " + key[14] + " " + key[15] + " " + key[16] + " " + key[17] + " " + key[18] + " " + key[19] + " " + key[20]);
}
System.out.println(key);
Player player = new Player();
Pattern pattern = new Pattern(key[0]);
player.play(pattern);
}
}