java中由字符串创建二维字符数组

public class ArrayOperation {
    public static char[][] getCharArray(String str){
        if (str.charAt(0) != '[' || str.charAt(1) != '[' || str.charAt(str.length() - 1) != ']' || str.charAt(str.length() - 2) != ']') {
            System.out.println("Wrong Input Format!");
            return null;
        }
        String[] strs = str.split("],\[");
        char[][] res = new char[strs.length][];
        for (int i = 0; i < res.length; i ++) {
            res[i] = strToCharArray(strs[i]);
        }
        return res;
    }

    private static char[] strToCharArray(String sourceStr) {
        if (sourceStr.length() == 3) {
            return new char[] {sourceStr.charAt(1)};
        }
        while (sourceStr.length() > 0 && sourceStr.charAt(0) == '[') {
            sourceStr = sourceStr.substring(1, sourceStr.length());
        }
        while (sourceStr.length() > 0 && sourceStr.charAt(sourceStr.length() - 1) == ']') {
            sourceStr = sourceStr.substring(0, sourceStr.length() - 1);
        }
        String[] strs = sourceStr.split(",");
        char[] res = new char[strs.length];
        for (int i = 0; i < strs.length; i ++) {
            res[i] = strs[i].charAt(1);
        }
        return res;
    }

    public static void main (String[] args){
        String str = "[["5","3",".",".","7",".",".",".","."],["6",".",".","1","9","5",".",".","."],[".","9","8",".",".",".",".","6","."],["8",".",".",".","6",".",".",".","3"],["4",".",".","8",".","3",".",".","1"],["7",".",".",".","2",".",".",".","6"],[".","6",".",".",".",".","2","8","."],[".",".",".","4","1","9",".",".","5"],[".",".",".",".","8",".",".","7","9"]]";
        System.out.println(str);
        print(ArrayOperation.getCharArray(str));
    }
}