密码加密例子

/**
		 * md5密碼加密
		 * @param args
		 * @return
		 * @throws NoSuchAlgorithmException
		 */
		public static void encryption (UserInfo user) {
			MessageDigest instance = null;
			try {
				instance = MessageDigest.getInstance("md5");
			} catch (NoSuchAlgorithmException e) {
				e.printStackTrace();
			}
			String secretKey = Config.SERECT_KEY.value();
			secretKey+=user.getPasswords();
			instance.update(secretKey.getBytes());
			byte[] digest = instance.digest();
			user.setPasswords(convertToHexString(digest));
		}
		/**
		 * 2進制轉到16進制-密碼還原
		 * @param data
		 * @return
		 */
		private static String convertToHexString(byte data[]) {
			StringBuffer strBuffer = new StringBuffer();
			for (int i = 0; i < data.length; i++) {
				strBuffer.append(Integer.toHexString(0xff & data[i]));
			}
			 
			return strBuffer.toString();
		}