code: public static RefundNotifyReqInfo decryptRefundNotifyReqInfo(String req_info, String key) {
  		try {
  			Cipher cipher = Cipher.getInstance("AES/ECB/NoPadding");
  			Key sKeySpec = new SecretKeySpec(DigestUtils.md5Hex(key).getBytes(), "AES");
  			cipher.init(Cipher.DECRYPT_MODE, sKeySpec);
  			byte[] resultByte = cipher.doFinal(Base64.decodeBase64(req_info));
  			String data = new String(PKCS7Encoder.decode(resultByte));
  			return XMLConverUtil.convertToObject(RefundNotifyReqInfo.class, data);
  		} catch (Exception e) {
  			logger.error("", e);
  		}
  		return null;
  	}
docs: 解密退款结果通知数据 <br>
  
  <i>
  解密失败解决方案：在官方网站下载JCE无限制权限策略文件（请到官网下载对应的版本) ,下载后解压。<br>
  可以看到local_policy.jar和US_export_policy.jar以及readme.txt，<br>
  将两个jar文件放到%JDK_HOME%\jre\lib\security目录下覆盖原来文件<br>
  
  JCE7 http://www.oracle.com/technetwork/java/javase/downloads/jce-7-download-432124.html<br>
  JCE8 http://www.oracle.com/technetwork/java/javase/downloads/jce8-download-2133166.html
  </i>
  
  @since 2.8.19
  
  @param req_info
  加密数据
  @param key
  支付key
  @return RefundNotifyReqInfo 解密失败返回 Null