沙箱环境下可以直接下载沙箱环境的APP进行测试，authCode就是支付宝客户端付钱中条码下的一窜数字。APP下载-沙箱工具

如有疑问请发issues

IJPay 接口

    /**
     * 条形码支付、声波支付
     * @param model
     * @param notifyUrl
     * @return {String}
     * @throws {AlipayApiException}
     */
    public static String tradePay(AlipayTradePayModel model, String notifyUrl) throws AlipayApiException {
        AlipayTradePayResponse response = tradePayToResponse(model,notifyUrl);
        return response.getBody();
    }
    /**
     * 交易支付接口
     * 条形码支付、声波支付
     * @param model
     * @param notifyUrl
     * @return {AlipayTradePayResponse}
     * @throws {AlipayApiException}
     */
    public static AlipayTradePayResponse tradePayToResponse(AlipayTradePayModel model, String notifyUrl) throws AlipayApiException{
        AlipayTradePayRequest request = new AlipayTradePayRequest();
        request.setBizModel(model);// 填充业务参数
        request.setNotifyUrl(notifyUrl);
        return AliPayApiConfigKit.getAliPayApiConfig().getAlipayClient().execute(request); // 通过AliPayApiConfigKit.getAliPayApiConfig().getAlipayClient()调用API，获得对应的response类
    }

代码示例

https://github.com/Javen205/IJPay-Demo

    /**
     * 条形码支付
     */
    public void tradePay() {
        String authCode = getPara("auth_code");
        String subject = "Javen 支付宝条形码支付测试";
        String totalAmount = "100";
        String notifyUrl = notify_domain + "/alipay/notify_url";

        AlipayTradePayModel model = new AlipayTradePayModel();
        model.setAuthCode(authCode);
        model.setSubject(subject);
        model.setTotalAmount(totalAmount);
        model.setOutTradeNo(StringUtils.getOutTradeNo());
        model.setScene("bar_code");
        try {
            String resultStr = AliPayApi.tradePay(model,notifyUrl);
            renderText(resultStr);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 条形码支付
     */
    @RequestMapping(value ="/tradePay")
    @ResponseBody
    public String  tradePay(@RequestParam("auth_code") String authCode) {
        String subject = "Javen 支付宝条形码支付测试";
        String totalAmount = "100";
        String notifyUrl = aliPayBean.getDomain() + "/alipay/notify_url";

        AlipayTradePayModel model = new AlipayTradePayModel();
        model.setAuthCode(authCode);
        model.setSubject(subject);
        model.setTotalAmount(totalAmount);
        model.setOutTradeNo(StringUtils.getOutTradeNo());
        model.setScene("bar_code");
        try {
            return AliPayApi.tradePay(model,notifyUrl);
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }