java 10 진 변환 N 진 변환 및 반전 도구 클래스

public class NumericConvertUtil {
	/**
	 *            
	 */
	final static char[] digits = { '0', '1', '2', '3', '4', '5', '6', '7', '8',
			'9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L',
			'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y',
			'Z' };

	/**
	 *                   
	 * 
	 * @param n       
	 * @param base      
	 * @return
	 */
	public static String toOtherBaseString(long n, int base) {
		long num = 0;
		if (n < 0) {
			num = ((long) 2 * 0x7fffffff) + n + 2;
		} else {
			num = n;
		}
		char[] buf = new char[32];
		int charPos = 32;
		while ((num / base) > 0) {
			buf[--charPos] = digits[(int) (num % base)];
			num /= base;
		}
		buf[--charPos] = digits[(int) (num % base)];
		return new String(buf, charPos, (32 - charPos));
	}

	/**
	 *         （     ）         
	 * 
	 * @param str        （     ）
	 * @param base      
	 * @return
	 */
	public static long toDecimalism(String str, int base) {
		char[] buf = new char[str.length()];
		str.getChars(0, str.length(), buf, 0);
		long num = 0;
		for (int i = 0; i < buf.length; i++) {
			for (int j = 0; j < digits.length; j++) {
				if (digits[j] == buf[i]) {
					num += j * Math.pow(base, buf.length - i - 1);
					break;
				}
			}
		}
		return num;
	}

	public static void main(String[] args) {
		System.out.println(toOtherBaseString(16857120L, 36));
		System.out.println(toDecimalism("A1B1AJASWDE", 36));
	}
}