<正则吃饺子> ：关于微信支付的简单总结说明（二）

关于微信退款

一、官方文档

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

二、退款流程图

注意：微信退款时候，需要证书服务，这里可以参见官方文档中的说明，包括证书的具体下载，解析等。（后面我也补充个证书解析的文件，方便理解）

一个百度文库的文档：https://wenku.baidu.com/view/754c78e93186bceb19e8bbcc.html

三、项目中使用的代码

拿来作个参考吧，方便记忆和理解

/**
     * 微信支付申请退款
     *
     * @param weChatPayRefund
     * @return
     */
    public boolean weChatPayRefundRequest(WeChatPayRefund weChatPayRefund, String source) {
        try {
            if (null == weChatPayRefund) {
                throw new ArgumentException("参数异常");
            }
            if (Strings.isNullOrEmpty(weChatPayRefund.getRefund_fee())) {
                throw new ArgumentException("退款金额为空");
            }
            if (Strings.isNullOrEmpty(weChatPayRefund.getOut_trade_no())) {
                throw new ArgumentException("原交易编号为空");
            }

            //退款金额，微信金额单位为分，系统为元，做换算
            int refundFee = new BigDecimal(weChatPayRefund.getRefund_fee())
                    .multiply(new BigDecimal(100)).intValue();
            weChatPayRefund.setRefund_fee(String.valueOf(refundFee));
            //订单总金额单位为分
            int totalFee = new BigDecimal(weChatPayRefund.getTotal_fee())
                    .multiply(new BigDecimal(100)).intValue();
            weChatPayRefund.setTotal_fee(String.valueOf(totalFee));
            //生成随机流水号
            String timeStr = System.currentTimeMillis() + "";
            weChatPayRefund.setOut_refund_no("TK" + timeStr);
            //退款单号为UUID
            weChatPayRefund.setNonce_str(UUIDUtil.randrom());
            //生成退款参数XML
            String xml = this.createRefundXml(weChatPayRefund, source);
            String refundURL = "https://api.mch.weixin.qq.com/secapi/pay/refund";
            ClientCustomSSL clientCustomSSL = new ClientCustomSSL();
            String result = "";
            if ("01".equals(source)) {
                result = clientCustomSSL.doRefund(refundURL, xml, weChatPkcs12, "B2B");
            } else if ("02".equals(source)) {
                result = clientCustomSSL.doRefund(refundURL, xml, b2cWeChatPkcs12, "B2C");
            } else if ("03".equals(source)) {
                result = clientCustomSSL.doRefund(refundURL, xml, b2cWeChatPkcs12_new, "B2C_NEW");
            }
            //请求返回结果
            result = result.replaceAll("\n", "").replaceAll("\r", "").replaceAll("\t", "");
            Document doc = DocumentHelper.parseText(result);
            
            Map<String, Object> resultMap = XmlMapHandle.Dom2Map(doc);
            String applyId = weChatPayRefund.getApplyId();
            StringHashMapper stringHashMapper = new StringHashMapper(WeChatPayRefund.class);
            WeChatPayRefund weChatPay = (WeChatPayRefund) stringHashMapper.fromHash(resultMap);
            ConvenienceRefund refund = createRefundInfo(weChatPayRefund);
　　　　　　　　//根据返回结果，处理一些自己的业务
            if (weChatPay.getReturn_code().equalsIgnoreCase("SUCCESS") && weChatPay.getResult_code().equalsIgnoreCase("SUCCESS")) {
                weChatPay.setApplyId(applyId);
                refund.setRefundStatus("1");
                this.rechargeOrderWriteDao.saveRefundInfo(refund);//保存退款信息
                int updateFlag = rechargeOrderWriteDao.updateOrderPayStatus(RedisType.PAY_STATUS2.getIndex(), weChatPayRefund.getOut_trade_no());
                if (updateFlag >= 1) {
                    //退款成功
                    //订单日志保存
                    ConvenienceOrderLog orderLog = new ConvenienceOrderLog();
                    orderLog.setOrderId(String.valueOf(weChatPayRefund.getOut_trade_no()));
                    orderLog.setStatusCode(50);
                    orderLog.setStatusName("退款成功");
                    this.saveConvenienceOrderLog(orderLog);
                    return true;
                } else {
                    //退款失败
                    return false;
                }
            } else {
                refund.setRefundStatus("0");
                this.rechargeOrderWriteDao.saveRefundInfo(refund);
                ConvenienceOrderLog orderLog = new ConvenienceOrderLog();
                orderLog.setOrderId(String.valueOf(weChatPayRefund.getOut_trade_no()));
                orderLog.setStatusCode(99);
                orderLog.setStatusName("退款失败");
                throw new BusinessException("退款失败：" + weChatPayRefund.getReturn_msg());
            }
        } catch (Exception e) {
            throw new BusinessException("退款失败：请联系管理员");
        }
    }

    /**
     * 根据订单来源生成退款参数XML
     *
     * @param weChatPayRefund
     * @param source
     * @return
     */
    public String createRefundXml(WeChatPayRefund weChatPayRefund, String source) {
        String appId = "";
        String mchId = "";
        String key = "";
        if ("01".equals(source)) {
            appId = weChatPayRefund.getB2b_appid_new();
            mchId = weChatPayRefund.getB2b_mch_id_new();
            key = weChatPayRefund.getB2b_appKey_new();
        } else if ("02".equals(source)) {
            appId = weChatPayRefund.getB2c_appid();
            mchId = weChatPayRefund.getB2c_mch_id();
            key = weChatPayRefund.getB2c_appKey();
        } else if ("03".equals(source)) {
            appId = weChatPayRefund.getB2c_appid_new();
            mchId = weChatPayRefund.getB2c_mch_id_new();
            key = weChatPayRefund.getB2c_appKey_new();
        }
        //生成退款签名
        SortedMap<String, String> packageParams = new TreeMap<String, String>();
        packageParams.put("appid", appId);
        packageParams.put("mch_id", mchId);
        packageParams.put("nonce_str", weChatPayRefund.getNonce_str());
        packageParams.put("out_trade_no", weChatPayRefund.getOut_trade_no());
        packageParams.put("out_refund_no", weChatPayRefund.getOut_refund_no());
        packageParams.put("total_fee", weChatPayRefund.getTotal_fee());
        packageParams.put("refund_fee", weChatPayRefund.getRefund_fee());
        packageParams.put("op_user_id", mchId);

        RequestHandler reqHandler = new RequestHandler(null, null);

        reqHandler.init(appId, "", key);
        String sign = reqHandler.createSign(packageParams);
        String xml = org.apache.commons.lang3.StringUtils.join("<xml>", "<appid>", appId,
                "</appid>", "<mch_id>", mchId, "</mch_id>", "<nonce_str>",
                weChatPayRefund.getNonce_str(), "</nonce_str>", "<sign><![CDATA[", sign,
                "]]></sign>", "<out_trade_no>", weChatPayRefund.getOut_trade_no(),
                "</out_trade_no>", "<out_refund_no>" + weChatPayRefund.getOut_refund_no(),
                "</out_refund_no>", "<total_fee>", weChatPayRefund.getTotal_fee(), "</total_fee>",
                "<refund_fee>" + weChatPayRefund.getRefund_fee(), "</refund_fee>",
                "<op_user_id>" + mchId, "</op_user_id>", "</xml>");
        return xml;
    }

四、引申与其他

（待续..）