关于微信和支付宝自动退款接口的接入总结

一：支付宝的自动退款接口接入

　　支付宝官方api：https://doc.open.alipay.com/doc2/apiDetail.htm?spm=a219a.7629065.0.0.PlTwKb&apiId=759&docType=4

　　支付宝的自动退款按照官方文档开发都非常明了，不做太多的累赘：

　　有一点不太清楚的地方是，在退款成功后没有返回支付宝自己的退款单号　

　　官方文档截图如下：

　部分代码如下：

public void orderPayRefund(OpsOrderRefundDetailModel refundDetailModel, String refundPrice) throws Exception{
    String appId = DataRequest.resources.getProperty("ali.app.appId");
    String publicKey = DataRequest.resources.getProperty("ali.public.key");
    AlipayClient alipayClient = new DefaultAlipayClient(
            "https://openapi.alipay.com/gateway.do",appId,PRIVATE_KEY,"json",
            "utf-8",publicKey,AlipayConstants.SIGN_TYPE_RSA);
    AlipayTradeRefundRequest request = new AlipayTradeRefundRequest();
    request.setBizContent("{" +
            "    "out_trade_no":""+refundDetailModel.getOutTradeNo()+""," +
            "    "refund_amount":"+refundPrice+"," +
            "    "refund_reason":"正常退款"," +
            "    "out_request_no":""+refundDetailModel.getId()+""" +
            "  }");
    AlipayTradeRefundResponse response = alipayClient.execute(request);
    if(response.isSuccess()){
        dealRefundSuccess(refundDetailModel,refundPrice,response.getTradeNo());
    } else {
        logger.error(response.getMsg()+"退款失败");
        throw new UserHintException(response.getMsg());
    }
}

二：微信的自动退款接口接入

　　微信官方api：https://pay.weixin.qq.com/wiki/doc/api/jsapi.php?chapter=9_4

　　微信退款比较麻烦的是需要证书的双向认证，并且有签名算法做签名认证。

　　官方文档截图如下：

　　

　对于证书的使用以及签名生成算法可以在官方文档中详细去阅读，部分代码如下：

public void refundApp(OpsOrderRefundDetailModel refundDetailModel,String refundPrice) throws Exception{
　　// 1.证书的使用（这个证书使用可以在官方文档证书使用里面有官方demo）
    KeyStore keyStore  = KeyStore.getInstance("PKCS12");
    InputStream instream = this.getClass().getResourceAsStream(DataRequest.resources.getProperty("weixin.app.cert"));
    try {
        keyStore.load(instream, DataRequest.resources.getProperty("weixin.app.mchId").toCharArray());
    } catch (Exception e){
        e.printStackTrace();
    }finally {
        instream.close();
    }
    // Trust own CA and all self-signed certs
    SSLContext sslcontext = SSLContexts.custom().loadKeyMaterial(keyStore,DataRequest.resources.getProperty("weixin.app.mchId").toCharArray()).build();
    // Allow TLSv1 protocol only
    SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(
            sslcontext,
            new String[] { "TLSv1" },
            null,
            SSLConnectionSocketFactory.BROWSER_COMPATIBLE_HOSTNAME_VERIFIER);
    CloseableHttpClient httpclient = HttpClients.custom()
            .setSSLSocketFactory(sslsf)
            .build();
　　//http请求创建
    HttpPost httppost = new HttpPost("https://api.mch.weixin.qq.com/secapi/pay/refund");
    UnifiedRefundRequest req = new UnifiedRefundRequest();
    req.setAppid(DataRequest.resources.getProperty("weixin.app.appId"));
    req.setMch_id(DataRequest.resources.getProperty("weixin.app.mchId"));
    req.setOut_trade_no(refundDetailModel.getOutTradeNo());
    req.setOut_refund_no(refundDetailModel.getId());
    req.setTotal_fee(refundDetailModel.getOrderPayedPrice().multiply(new BigDecimal(100)).intValue());
    req.setRefund_fee(new BigDecimal(refundPrice).multiply(new BigDecimal(100)).intValue());
    req.setOp_user_id("admin");
　　//　这里createXml 方法已经完成了签名
    String xml = req.createXml();
　　//<xml>
   //　　<appid>wx2421b1c4370ec43b</appid>
   //　　<mch_id>10000100</mch_id>
   //　　<nonce_str>6cefdb308e1e2e8aabd48cf79e546a02</nonce_str>
   //　　<op_user_id>10000100</op_user_id>
   //　 <out_refund_no>1415701182</out_refund_no>
   //　 <out_trade_no>1415757673</out_trade_no>
   //　　 <refund_fee>1</refund_fee>
   //　　<total_fee>1</total_fee>
   //　　<transaction_id></transaction_id>
   //　 <sign>FE56DD4AA85C0EECA82C35595A69E153</sign>  
　　//</xml>
　　//上面注掉的<xml>就是createXml的结果 红色的地方就是签名
    StringEntity entity = new StringEntity(xml, "UTF-8");
    httppost.setEntity(entity);
　　//退款接口请求结果接受和处理
    CloseableHttpResponse responseEntry = httpclient.execute(httppost);
    HttpEntity resEntity = responseEntry.getEntity();
    String returnObj = (resEntity == null) ? null : EntityUtils.toString(resEntity, Consts.UTF_8);
    UnifiedOrderResponse resp = AbstractWxResponse.toBean(returnObj, UnifiedOrderResponse.class);
    resp.toVerify();
    if("SUCCESS".equals(resp.getResult_code())){
        dealRefundSuccess(refundDetailModel,refundPrice,resp.getRefund_id());
    }else{
        logger.error(resp.getErr_code_des()+"退款失败");
        throw new UserHintException(resp.getErr_code_des());
    }
}

　简单的一个总结，希望能对大家有所帮助或者启发，当然最直接的东西还是看官方文档。