如上是本人一位朋友的公司出的研發小測試，小朋友是一臉懵逼啊！

分析：進位制轉換思路：10進位制除以15商和餘數，反覆拿商除以15獲得商和餘數，類推，知道商為0，停止；

以235表示為10A為例分析：

235/15 = 15 餘數10

15/15 = 1 餘數 0

1/15 = 0 餘數 1

得到資料10, 0, 1， 反序結果為1, 0, 10, 對比結果： 1-》1， 0-》0, 10-》A, 所以235表示的十五進位制數為：10A；

具體實現如下：

@Test
	public void test() {
		Scanner scanner = new Scanner(System.in);
		System.out.println("請輸入十進位制數字:");
		/**
		 * Integer.parseInt(scanner.next(), 10); 10 代表的預設是10進位制的
		 * Character.MIN_RADIX=2和Character.MAX_RADIX=36
		 * parseInt(String s, int radix)引數中radix的範圍是在2~36之間，超出範圍會拋異常。其中s的長度也不能超出7，否則也會拋異常。
		 */
		Integer in = Integer.parseInt(scanner.next(), 10);
		List<Object> list = new ArrayList<Object>();
		while (true) {
			list.add(in % 15); // 取餘數
			in = in / 15; // 取餘數
			if (in == 0) { // 停止迴圈
				break;
			}
		}
		StringBuffer str = new StringBuffer(); // 拼接字串
		// 倒排
		for (int i = list.size() - 1; i >= 0; i--) {
			int number = (int) list.get(i);
			if (number == 10) {
				str.append("A");
			} else if (number == 11) {
				str.append("B");
			} else if (number == 12) {
				str.append("C");
			} else if (number == 13) {
				str.append("D");
			} else if (i == 14) {
				str.append("E");
			} else {
				str.append(number);
			}
		}
		System.out.println(str);
		//關流
		scanner.close(); 
	}
 

parseInt(String s, int radix)原始碼：

    if (s == null) {
        throw new NumberFormatException("null");
    }

    if (radix < Character.MIN_RADIX) {
        throw new NumberFormatException("radix " + radix +
                                            " less than Character.MIN_RADIX");
    }

    if (radix > Character.MAX_RADIX) {
         throw new NumberFormatException("radix " + radix +
                                            " greater than Character.MAX_RADIX");
    }


    /**
     * The minimum radix available for conversion to and from strings.
     * The constant value of this field is the smallest value permitted
     * for the radix argument in radix-conversion methods such as the
     * {@code digit} method, the {@code forDigit} method, and the
     * {@code toString} method of class {@code Integer}.
     *
     * @see     Character#digit(char, int)
     * @see     Character#forDigit(int, int)
     * @see     Integer#toString(int, int)
     * @see     Integer#valueOf(String)
     */
    public static final int MIN_RADIX = 2;

    /**
     * The maximum radix available for conversion to and from strings.
     * The constant value of this field is the largest value permitted
     * for the radix argument in radix-conversion methods such as the
     * {@code digit} method, the {@code forDigit} method, and the
     * {@code toString} method of class {@code Integer}.
     *
     * @see     Character#digit(char, int)
     * @see     Character#forDigit(int, int)
     * @see     Integer#toString(int, int)
     * @see     Integer#valueOf(String)
     */
    public static final int MAX_RADIX = 36;