JAVA数字转换为汉字

public static String CastToChineseNumber(String num) {
        String CNum = num;// 設置將要返回的數字等於輸入的數字
        if (CheckNum(CNum)) {
            switch (num.length()) {
            case 0:// 如果沒有輸入數字
                CNum = "N/A"; // 未知
                break;
            case 1:// 如果是1位的數字
                CNum = GetCNum(num);
                break;
            case 2:// 2位的數字
                if (num.substring(1).equals("0"))// 處理 10,20,3090這類數字
                {
                    if (num.substring(0, 1).equals("1")) {
                        CNum = "十";
                    } else {
                        CNum = GetCNum(num.substring(0, 1)) + "十";
                    }
                } else if (num.substring(0, 1).equals("1"))// 處理11轉換為 十一 而不是一十一
                {
                    CNum = "十" + GetCNum(num.substring(1));
                } else {
                    CNum = GetCNum(num.substring(0, 1)) + "十"
                            + GetCNum(num.substring(1));
                }
                break;
            case 3:// 如果是3位的數字
                CNum = GetCNum(num.substring(0, 1)) + "百"
                        + GetCNum(num.substring(1, 2)) + "十"
                        + GetCNum(num.substring(2));
                break;
            default:
                break;
            }
        }        
        return CNum;

    }

    public static boolean CheckNum(String num) {
        List<String> al = new ArrayList<String>();
        String[] ss = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" };
        al = Arrays.asList(ss);
        // String Num = "0123456789";
        char[] nums = num.toCharArray();
        boolean isNum = false;
        for (char n : nums) {            
            if (al.contains(String.valueOf(n))) {
                isNum = true;
            } else {
                isNum = false;
                break;
            }
        }
        return isNum;
    }

    /**
     * 獲取數字對應的漢字
     * 
     * @param num
     *            輸入的數字
     * @return 返回的數字
     */
    public static String GetCNum(String num) {
        String Cnum = "";
        switch (Integer.parseInt(num)) {
        case 0:
            Cnum = "零";
            break;
        case 1:
            Cnum = "一";
            break;
        case 2:
            Cnum = "二";
            break;
        case 3:
            Cnum = "三";
            break;
        case 4:
            Cnum = "四";
            break;
        case 5:
            Cnum = "五";
            break;
        case 6:
            Cnum = "六";
            break;
        case 7:
            Cnum = "七";
            break;
        case 8:
            Cnum = "八";
            break;
        case 9:
            Cnum = "九";
            break;
        }
        return Cnum;
    }