ERROR: api.mch.weixin.qq.com:443 failed to respond [微信退款]

1、问题

ERROR: api.mch.weixin.qq.com:443 failed to respond

此报错是因为调用微信退款请求需要双向证书

获取API证书

此路径下载即可
微信商户平台(pay.weixin.qq.com)–>账户中心–>账户设置–>API安全

一共三个文件，java开发者只需要 apiclient_cert.p12文件即可

导入安装证书，证书密码默认为商户号

2、代码实现

    public BaseResponse<RefundLog> wxpayRefund(PaymentLog paymentLog, BigDecimal refundAmount) throws Exception {

        Map<String, Object> parameterMap = new HashMap<>();
        parameterMap.put(APPID, 公众账号ID);
        parameterMap.put(MCHID, 商户号);
        parameterMap.put(NONCE_STR, 随机字符串);
        parameterMap.put(OUT_TRADE_NO, 商户订单号);
        parameterMap.put(OUT_REFUND_NO, 商户退款单号);
        parameterMap.put(TOTAL_FEE, 订单金额);
        parameterMap.put(REFUND_FEE, 退款金额);
        parameterMap.put(SIGN_PARAMETER_NAME, 签名);

		//微信退款信息要以xml格式传递
        String postDataXML = XMLUtils.getRequestXml(parameterMap);
        log.info("支付参数准备XML：{}", postDataXML);
		//请求退款连接
        String result = wxRefundLink(postDataXML, mch_id);
		//返回这转为map
        Map responseMap = XMLUtils.fromXML(result);
		//退款状态业务处理
        if (FAIL.equals(responseMap.get(RETURN_CODE))) {
            return BaseResponse.successResponse("微信退款失败,"+responseMap.get(RETURN_MSG));
        } else{
            if (SUCCESS.equals(responseMap.get(RESULT_CODE))) {
                return BaseResponse.successResponse("微信退款完成");
            } else {
                //出现业务错误
                String errorCodeDes = String.valueOf(responseMap.get(ERR_CODE_DES));
                log.error("err_code_des:" + errorCodeDes);
                return BaseResponse.successResponse("退款失败"+errorCodeDes);
            }
        }

    }


	
    private String  wxRefundLink(String postDataXML,String mch_id) throws Exception{
        CloseableHttpClient httpClient = null;
        CloseableHttpResponse httpResponse = null;
        try{
            //获取微信退款证书
            KeyStore keyStore = getCertificate(mch_id);
            SSLContext sslContext = SSLContexts.custom().loadKeyMaterial(keyStore, mch_id.toCharArray()).build();
            SSLConnectionSocketFactory sslf = new SSLConnectionSocketFactory(sslContext);
            httpClient = HttpClients.custom().setSSLSocketFactory(sslf).build();
            HttpPost httpPost = new HttpPost(WX_REFUND_URL);//退款接口

            StringEntity reqEntity = new StringEntity(postDataXML);
            // 设置类型
            reqEntity.setContentType("application/x-www-form-urlencoded");
            httpPost.setEntity(reqEntity);
            String result = null;
            httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            if (Validator.isNotNullOrEmpty(httpEntity)) {
                result = EntityUtils.toString(httpEntity, UTF8);
                EntityUtils.consume(httpEntity);
            }
            return result;
        }finally {//关流
            httpClient.close();
            httpResponse.close();
        }

    }
	
	    /**
     *
     * @description: 获取微信退款证书
     * @param mch_id
     * @auther: sean.xu
     * @date: 2019/8/13 15:11
     */
    private KeyStore getCertificate(String mch_id){
        //try-with-resources 关流
        try (FileInputStream inputStream = new FileInputStream(new File("D:\\wx\\1248201701_20190812_cert\\apiclient_cert.p12"))) {
            KeyStore keyStore = KeyStore.getInstance(PKCS12);
            keyStore.load(inputStream, mch_id.toCharArray());
            return keyStore;
        } catch (Exception e) {
            throw new RuntimeException(e.getMessage(), e);
        }
    }

3、效果截图

四、友情链接

退款文档
https://pay.weixin.qq.com/wiki/doc/api/app/app.php?chapter=9_4&index=6

签名 证书
https://pay.weixin.qq.com/wiki/doc/api/app/app.php?chapter=4_3