code: public static String byteArrayToHexString(byte[] b) {
  		StringBuilder hs = new StringBuilder();
  		String stmp;
  		for (int n = 0; b != null && n < b.length; n++) {
  			stmp = Integer.toHexString(b[n] & 0XFF);
  			if (stmp.length() == 1)
  				hs.append('0');
  			hs.append(stmp);
  		}
  		return hs.toString().toLowerCase();
  	}
docs: 将加密后的字节数组转换成字符串