code: @RequestMapping(value = "/qrpay")
      public void qrPay(
              @RequestParam("orderNumber") String orderNumber,
              HttpServletResponse response){
          try {
              String qrUrl = wepaySupport.qrPay(orderNumber);
              response.sendRedirect(qrUrl);
          } catch (IOException e) {
              log.error("failed to qr pay(orderNumber={}), cause: {}",
                      orderNumber, e.getMessage());
          }
      }
docs: 二维码支付
  @param orderNumber 商户订单号