public void refund(AcopayRefundRequestModel refundRequestModel) {

  // 翼辉支付平台公钥
  String acopayPublicKey = "<acopayPublicKey>";
  // 商户私钥
  String mchPrivateKey = "<yourMchPrivateKey>";
  // 商户号
  String mchNo = "<yourMchNo>";
  // 商户退款结果通知地址
  String refundNotifyUrl = "<yourRefundNotifyUrl>";
        
  // 根据商户实际业务进行参数校验
  // 根据商户订单规则生成退款单号
  refundRequestModel.setMchRefundNo(AcopayCommonUtil.getRandomString(40));
  // 填写商户的退款通知地址
  refundRequestModel.setNotifyUrl(refundNotifyUrl);

  try {
    // 创建 AcopayClient 实例
    AcopayClient acopayClient = new DefaultAcopayClient(acopayPublicKey, mchPrivateKey, mchNo);
    // 发起退款请求
    AcopayResponse<AcopayRefundResponseModel> refundAcopayResponse = acopayClient.refund(refundRequestModel);

    if (refundAcopayResponse.statusSuccessful()){
      log.info("退款接口返回：{}", refundAcopayResponse);
      // 获取业务数据
      AcopayRefundResponseModel data = refundAcopayResponse.getData();
      // 业务请求成功处理
    } else {
      // 业务请求失败处理
      log.info("退款接口业务失败，返回状态码：{}， 返回信息：{}， 异常信息：{}",
      refundAcopayResponse.getStatus(), refundAcopayResponse.getMessage(),
      refundAcopayResponse.getFieldErrors());
    }
  } catch (AcopayException e) {
    // 进行异常处理
    log.error("退款请求异常", e);
  }
}