笔试题--请设计一个函数，输入10进制数字，输出62进制数字

    private static char[] charSet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".toCharArray();

　　 /**
     * 将10进制转化为62进制
     *
     * @param number 将要转换的10进制数字
     * @param length 转化成的62进制长度，不足length长度的话高位补0，否则不改变什么
     * @return
     */
    public static String convert10To62(long number, int length) {
        Long rest = number;
        Stack<Character> stack = new Stack<Character>();
        StringBuilder result = new StringBuilder(0);
        while (rest != 0) {
            stack.add(charSet[new Long((rest - (rest / 62) * 62)).intValue()]);
            rest = rest / 62;
        }
        for (; !stack.isEmpty(); ) {
            result.append(stack.pop());
        }
        int result_length = result.length();
        StringBuilder temp0 = new StringBuilder();
        for (int i = 0; i < length - result_length; i++) {
            temp0.append('0');
        }
        return temp0.toString() + result.toString();
    }