java程序：看看我错哪里了

Question

老师留的作业：将小写数字转换成大写且带单位

我的程序

import java.util.Scanner;
import java.util.Arrays;
class Zi{

public static void main(String[] args) {

    char[] zi = {'零','壹','贰','叁','肆','伍','陆','柒','捌','玖'};
    char[] level = {' ','拾','百','千','万','拾','百','千','亿','拾','百','千'};
    Scanner sc = new Scanner(System.in);
    System.out.println("#");
    String hanzi = sc.next();
    char[] a = hanzi.toCharArray();

    int[] m = new int[a.length];
    char[] n = new char[2*(a.length)];

    for(int i = 0; i < a.length; i++){
        m[i] = a[i] - '0';
    }

    for(int i = 0; i < 2 *(a.length); i += 2){
        n[i] = zi[m[i]];
        n[i + 1] = level[a.length - i] ;
    }

    String output = new String(n);
    System.out.println(output);
}

}

程序可以编译
但运行就会出错 像这样：
d:\code\0331>javac -encoding utf8 Zi.java

d:\code\0331>java Zi
#
112234
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 6
at Zi.main(Zi.java:22)

求大神解答 感激不敬

Answer 1

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 6
这个错是说你数组越界了
at Zi.main(Zi.java:22)
说明数组越界是第22行导致的，你再看看？