Java集成微信小程序支付和退款

ゝ一世哀愁。 2024-03-22 11:16 90阅读 0赞

微信支付文档：[https://pay.weixin.qq.com/wiki/doc/apiv3/open/pay/chapter1\_1\_1.shtml][https_pay.weixin.qq.com_wiki_doc_apiv3_open_pay_chapter1_1_1.shtml]

微信退款文档：[https://pay.weixin.qq.com/wiki/doc/apiv3/apis/chapter3\_1\_9.shtml][https_pay.weixin.qq.com_wiki_doc_apiv3_apis_chapter3_1_9.shtml]

#### 1、微信小程序支付 ####

##### 前提 #####

在进行对接微信支付之前，我们首先需要将以下几点准备好：

*  申请APPID
 *  申请商户号
 *  小程序开通微信支付，绑定已经申请好的商户号。登录小程序后台（mp.weixin.qq.com）。点击左侧导航栏的微信支付，在页面中进行开通。（开通申请要求小程序已发布上线）

##### 注意事项 #####

*  appid必须为最后拉起收银台的小程序appid；
 *  mch\_id为和appid成对绑定的支付商户号，收款资金会进入该商户号；
 *  trade\_type请填写JSAPI；
 *  openid为appid对应的用户标识，即使用wx.login接口获得的openid。

本文主要记录后端步骤，前端步骤无非就是获取后端数据然后调用提供的API进行支付，大家可自行查看官方文档。

##### 1. 支付业务流程图 #####

![\[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-JNr92RdW-1683010524685)(E:\\PRD\\Images\\image-20230502113439837.png)\]][img-JNr92RdW-1683010524685_E_PRD_Images_image-20230502113439837.png]

##### 2. 导入依赖 #####

implementation group: 'com.github.wechatpay-apiv3', name: 'wechatpay-apache-httpclient', version: '0.4.7'
    implementation group: 'com.github.wxpay',name: 'wxpay-sdk',version: '0.0.3'

##### 3. 编写相关工具类 #####

###### 解析Xml工具类 ######

/**
     * @author zzw
     * @description TODO 解析xml工具类
     * @date 2023-04-28 14:02
     */
    public class XMLUtil {
          
    
    	/**  
         * 瑙ｆ瀽xml,杩斿洖绗竴绾у厓绱犻敭鍊煎銆傚鏋滅锟�?绾у厓绱犳湁瀛愯妭鐐癸紝鍒欐鑺傜偣鐨勶拷?锟芥槸瀛愯妭鐐圭殑xml鏁版嵁锟�?  
         * @param strxml  
         * @author Lyp
         * @return  
         * @throws JDOMException  
         * @throws IOException  
         */    
        public static Map doXMLParse(String strxml) throws JDOMException, IOException {
            
            strxml = strxml.replaceFirst("encoding=\".*\"", "encoding=\"UTF-8\"");  
            if(null == strxml || "".equals(strxml)) {
            
                return null;    
            }    
    
            Map m = new HashMap();    
    
            InputStream in = new ByteArrayInputStream(strxml.getBytes("UTF-8"));    
            SAXBuilder builder = new SAXBuilder();    
            Document doc = builder.build(in);    
            Element root = doc.getRootElement();    
            List list = root.getChildren();    
            Iterator it = list.iterator();    
            while(it.hasNext()) {
            
                Element e = (Element) it.next();    
                String k = e.getName();    
                String v = "";    
                List children = e.getChildren();    
                if(children.isEmpty()) {
            
                    v = e.getTextNormalize();    
                } else {
            
                    v = XMLUtil.getChildrenText(children);    
                }    
    
                m.put(k, v);    
            }    
    
            //鍏抽棴锟�?    
            in.close();    
    
            return m;    
        }    
        
        /**  
         * 鑾峰彇瀛愮粨鐐圭殑xml  
         * @param children  
         * @return String  
         */    
        public static String getChildrenText(List children) {
            
            StringBuffer sb = new StringBuffer();    
            if(!children.isEmpty()) {
            
                Iterator it = children.iterator();    
                while(it.hasNext()) {
            
                    Element e = (Element) it.next();    
                    String name = e.getName();    
                    String value = e.getTextNormalize();    
                    List list = e.getChildren();    
                    sb.append("<" + name + ">");    
                    if(!list.isEmpty()) {
            
                        sb.append(XMLUtil.getChildrenText(list));    
                    }    
                    sb.append(value);    
                    sb.append("</" + name + ">");    
                }    
            }    
    
            return sb.toString();    
        }
    }

**微信支付工具类**

/**
     * @author zzw
     * @description TODO 微信支付工具类
     * @date 2023-04-28 14:02
     */
    public class WXPayUtil {
        
    	/**
         * XML????????????Map
         * @param strXML XML?????
         * @return XML?????????Map
         * @throws Exception
         * /
    	public static Map<String, String> xmlToMap(String strXML) throws Exception {
    		try {
    			Map<String, String> data = new HashMap<String, String>();
                DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
                DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
                InputStream stream = new ByteArrayInputStream(strXML.getBytes("UTF-8"));
                org.w3c.dom.Document doc = documentBuilder.parse(stream);
                doc.getDocumentElement().normalize();
                NodeList nodeList = doc.getDocumentElement().getChildNodes();
                for (int idx = 0; idx < nodeList.getLength(); ++idx) {
                	Node node = nodeList.item(idx);
                    if (node.getNodeType() == Node.ELEMENT_NODE) {
                    	org.w3c.dom.Element element = (org.w3c.dom.Element) node;
                        data.put(element.getNodeName(),element.getTagName());
                    }
                }
                try {
                	stream.close();
                } catch (Exception ex) {
                   // do nothing
                }
                return data;
    		} catch (Exception ex) {
    			WXPayUtil.getLogger().warn("Invalid XML, can not convert to map. Error message: {}. XML content: {}", ex.getMessage(), strXML);
                       throw ex;
            }
    
    	}
       
       /**
         * ??ap?????ML?????????
         * @param data Map??????
         * @return XML?????????
         * @throws Exception
         */
        public static String mapToXml(Map<String, String> data) throws Exception {
        
            DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder documentBuilder= documentBuilderFactory.newDocumentBuilder();
            org.w3c.dom.Document document = documentBuilder.newDocument();
            org.w3c.dom.Element root = document.createElement("xml");
            document.appendChild(root);
            for (String key: data.keySet()) {
        
                String value = data.get(key);
                if (value == null) {
        
                    value = "";
                }
                value = value.trim();
                org.w3c.dom.Element filed = document.createElement(key);
                filed.appendChild(document.createTextNode(value));
                root.appendChild(filed);
            }
            TransformerFactory tf = TransformerFactory.newInstance();
            Transformer transformer = tf.newTransformer();
            DOMSource source = new DOMSource(document);
            transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
            transformer.setOutputProperty(OutputKeys.INDENT, "yes");
            StringWriter writer = new StringWriter();
            StreamResult result = new StreamResult(writer);
            transformer.transform(source, result);
            String output = writer.getBuffer().toString(); //.replaceAll("\n|\r", "");
            try {
        
                writer.close();
            }
            catch (Exception ex) {
        
            }
            return output;
        }
        
        /**
         * ?????? sign ?? XML ????????
         * @param data Map??????
         * @param key API???
         * @return ???sign?????ML
         */
        public static String generateSignedXml(final Map<String, String> data, String key) throws Exception {
        
            return generateSignedXml(data, key, SignType.MD5);
        }
    
        /**
         * ?????? sign ?? XML ????????
         * @param data Map??????
         * @param key API???
         * @param signType ??????
         * @return ???sign?????ML
         */
        public static String generateSignedXml(final Map<String, String> data, String key, SignType signType) throws Exception {
        
            String sign = generateSignature(data, key, signType);
            data.put(WXPayConstants.FIELD_SIGN, sign);
            return mapToXml(data);
        }
    
        /**
         * ????????????
         *
         * @param xmlStr XML??????
         * @param key API???
         * @return ?????????
         * @throws Exception
         */
        public static boolean isSignatureValid(String xmlStr, String key) throws Exception {
        
            Map<String, String> data = xmlToMap(xmlStr);
            if (!data.containsKey(WXPayConstants.FIELD_SIGN) ) {
        
                return false;
            }
            String sign = data.get(WXPayConstants.FIELD_SIGN);
            return generateSignature(data, key).equals(sign);
        }
    
        /**
         * ????????????????????ign???????????alse?????D5?????
         *
         * @param data Map??????
         * @param key API???
         * @return ?????????
         * @throws Exception
         */
        public static boolean isSignatureValid(Map<String, String> data, String key) throws Exception {
        
            return isSignatureValid(data, key, SignType.MD5);
        }
    
        /**
         * ????????????????????ign???????????alse??
         *
         * @param data Map??????
         * @param key API???
         * @param signType ??????
         * @return ?????????
         * @throws Exception
         */
        public static boolean isSignatureValid(Map<String, String> data, String key, SignType signType) throws Exception {
        
            if (!data.containsKey(WXPayConstants.FIELD_SIGN) ) {
        
                return false;
            }
            String sign = data.get(WXPayConstants.FIELD_SIGN);
            return generateSignature(data, key, signType).equals(sign);
        }
    
        /**
         * ??????
         *
         * @param data ????????
         * @param key API???
         * @return ???
         */
        public static String generateSignature(final Map<String, String> data, String key) throws Exception {
        
            return generateSignature(data, key, SignType.MD5);
        }
    
        /**
         * ??????. ?????????sign_type?????????signType????????????
         *
         * @param data ????????
         * @param key API???
         * @param signType ??????
         * @return ???
         */
        public static String generateSignature(final Map<String, String> data, String key, SignType signType) throws Exception {
        
            Set<String> keySet = data.keySet();
            String[] keyArray = keySet.toArray(new String[keySet.size()]);
            Arrays.sort(keyArray);
            StringBuilder sb = new StringBuilder();
            for (String k : keyArray) {
        
                if (k.equals(WXPayConstants.FIELD_SIGN)) {
        
                    continue;
                }
                if (data.get(k).trim().length() > 0) // ??????????????????
                    sb.append(k).append("=").append(data.get(k).trim()).append("&");
            }
            sb.append("key=").append(key);
            if (SignType.MD5.equals(signType)) {
        
                return MD5(sb.toString()).toUpperCase();
            }
            else if (SignType.HMACSHA256.equals(signType)) {
        
                return HMACSHA256(sb.toString(), key);
            }
            else {
        
                throw new Exception(String.format("Invalid sign_type: %s", signType));
            }
        }
        
        /**
         * ??????????? Nonce Str
         *
         * @return String ????????
         */
        public static String generateNonceStr() {
        
            return UUID.randomUUID().toString().replaceAll("-", "").substring(0, 32);
        }
        
       /**
         * ??? MD5
         *
         * @param data ????????
         * @return MD5???
         */
        public static String MD5(String data) throws Exception {
        
            MessageDigest md = MessageDigest.getInstance("MD5");
            byte[] array = md.digest(data.getBytes("UTF-8"));
            StringBuilder sb = new StringBuilder();
            for (byte item : array) {
        
                sb.append(Integer.toHexString((item & 0xFF) | 0x100).substring(1, 3));
            }
            return sb.toString().toUpperCase();
        }
    
        /**
         * ??? HMACSHA256
         * @param data ????????
         * @param key ???
         * @return ??????
         * @throws Exception
         */
        public static String HMACSHA256(String data, String key) throws Exception {
        
            Mac sha256_HMAC = Mac.getInstance("HmacSHA256");
            SecretKeySpec secret_key = new SecretKeySpec(key.getBytes("UTF-8"), "HmacSHA256");
            sha256_HMAC.init(secret_key);
            byte[] array = sha256_HMAC.doFinal(data.getBytes("UTF-8"));
            StringBuilder sb = new StringBuilder();
            for (byte item : array) {
        
                sb.append(Integer.toHexString((item & 0xFF) | 0x100).substring(1, 3));
            }
            return sb.toString().toUpperCase();
        }
    
        /**
         * ???
         * @return
         */
        public static Logger getLogger() {
        
            Logger logger = LoggerFactory.getLogger("wxpay java sdk");
            return logger;
        }
    
        /**
         * ?????????????????
         * @return
         */
        public static long getCurrentTimestamp() {
        
            return System.currentTimeMillis()/1000;
        }
    
        /**
         * ??????????????????
         * @return
         */
        public static long getCurrentTimestampMs() {
        
            return System.currentTimeMillis();
        }
    
        /**
         * ??? uuid?? ?????????????????? nonce_str
         * @return
         */
        public static String generateUUID() {
        
            return UUID.randomUUID().toString().replaceAll("-", "").substring(0, 32);
        }
        
        /**
         * ??????ip???
         * @return
         */
        public static String localip(){
        
            String ip=null;
            Enumeration allNetInterfaces;
            try {
        
                allNetInterfaces=NetworkInterface.getNetworkInterfaces();
                while(allNetInterfaces.hasMoreElements()){
        
                NetworkInterface netInterface=(NetworkInterface)allNetInterfaces.nextElement();
                List<InterfaceAddress> InterfaceAddress=netInterface.getInterfaceAddresses();
                for(InterfaceAddress add:InterfaceAddress){
        
                    InetAddress Ip=add.getAddress();
                    if(Ip!=null&&Ip instanceof Inet4Address){
        
                        ip=Ip.getHostAddress();
                    }
    
                    }
                }
            } catch (SocketException e) {
        
                System.out.println("??????ip???????????");
                e.printStackTrace();
    
            }
            return ip;
        }
    }

###### 支付相关工具类 ######

public class PayForUtil {
          
    
    	private static Logger lg=Logger.getLogger(PayForUtil.class);  
    
    	/**  
         * 是否签名正确,规则是:按参数名称a-z排序,遇到空值的参数不参加签名。  
         * @return boolean  
         */    
    	public static boolean isTenpaySign(String characterEncoding, SortedMap<Object, Object> packageParams, String API_KEY) {
            
    		StringBuffer sb = new StringBuffer();    
         	Set es = packageParams.entrySet();    
         	Iterator it = es.iterator();    
         	while(it.hasNext()) {
            
    			Map.Entry entry = (Map.Entry)it.next();    
             	String k = (String)entry.getKey();    
             	String v = (String)entry.getValue();    
             	if(!"sign".equals(k) && null != v && !"".equals(v)) {
            
                	sb.append(k + "=" + v + "&");    
             	}    
         	}    
    		sb.append("key=" + API_KEY); 
            //算出摘要    
            String mysign = MD5Util.MD5Encode(sb.toString(), characterEncoding).toLowerCase();    
            String tenpaySign = ((String)packageParams.get("sign")).toLowerCase();    
            return tenpaySign.equals(mysign);    
        }    
        /**  
         * @Description：sign签名  
         * @param characterEncoding  
         *            编码格式  
         * @param parameters  
         *            请求参数  
         * @return  
         */    
        public static String createSign(String characterEncoding, SortedMap<Object, Object> packageParams, String API_KEY) {
            
            StringBuffer sb = new StringBuffer();    
            Set es = packageParams.entrySet();    
            Iterator it = es.iterator();    
            while (it.hasNext()) {
            
                Map.Entry entry = (Map.Entry) it.next();    
                String k = (String) entry.getKey();    
                String v = (String) entry.getValue();    
                if (null != v && !"".equals(v) && !"sign".equals(k) && !"key".equals(k)) {
            
                    sb.append(k + "=" + v + "&");    
                }    
            }    
            sb.append("key=" + API_KEY);    
            String sign = MD5Util.MD5Encode(sb.toString(), characterEncoding).toUpperCase();    
            return sign;    
        }    
    
        /**  
         * @Description：将请求参数转换为xml格式的string  
         * @param parameters  
         *            请求参数  
         * @return  
         */    
        public static String getRequestXml(SortedMap<Object,Object> parameters) {
            
            StringBuffer sb = new StringBuffer();    
            sb.append("<xml>");    
            Set es = parameters.entrySet();    
            Iterator it = es.iterator();    
            while (it.hasNext()) {
            
                Map.Entry entry = (Map.Entry) it.next();    
                String k = (String) entry.getKey();    
                String v = (String) entry.getValue();    
                if ("attach".equalsIgnoreCase(k) || "body".equalsIgnoreCase(k) || "sign".equalsIgnoreCase(k)) {
            
                    sb.append("<" + k + ">" + "<![CDATA[" + v + "]]></" + k + ">");    
                } else {
            
                    sb.append("<" + k + ">" + v + "</" + k + ">");    
                }    
            }    
            sb.append("</xml>");    
            return sb.toString();    
        }    
    
        /**  
         * 取出一个指定长度大小的随机正整数.  
         *   
         * @param length  
         *            int 设定所取出随机数的长度。length小于11  
         * @return int 返回生成的随机数。  
         */    
        public static int buildRandom(int length) {
            
            int num = 1;    
            double random = Math.random();    
            if (random < 0.1) {
            
                random = random + 0.1;    
            }    
            for (int i = 0; i < length; i++) {
            
                num = num * 10;    
            }    
            return (int) ((random * num));    
        }    
    
        /**  
         * 获取当前时间 yyyyMMddHHmmss  
         * @return String  
         */    
        public static String getCurrTime() {
            
            Date now = new Date();    
            SimpleDateFormat outFormat = new SimpleDateFormat("yyyyMMddHHmmss");    
            String s = outFormat.format(now);    
            return s;    
        }  
    }

###### 金额换算工具类 ######

public class Utils {
        
        public static String getFee(String fee) {
        
            BigDecimal a = new BigDecimal(fee).multiply(BigDecimal.valueOf(100));
            fee = String.valueOf(a);//浮点变量a转换为字符串str
            //先把小数点后的0截取掉
            int idx = fee.lastIndexOf(".");//查找小数点的位置
            String strNum = null;
            if (idx != -1) {
        
                strNum = fee.substring(0, idx);//截取从字符串开始到小数点位置的字符串，就是整数部分
            } else {
        
                strNum = fee;
            }
            //将截取后的金额转换为整数
            int num = Integer.valueOf(strNum);//把整数部分通过Integer.valueof方法转换为数字
            //工行金额以分为单位，将金额* 100
            return num + "";
        }
        
        public static boolean isNumeric(String str){
        
            for (int i = str.length();--i>=0;){
        
                if (!Character.isDigit(str.charAt(i))){
        
                    return false;
                }
            }
            return true;
        }
    
        public static void main(String[] args) {
        
            System.out.println(getFee("2.50"));
        }
    }

##### 4. 生成预支付交易单 #####

商户系统先调用该接口在微信支付服务后台生成预支付交易单，返回正确的预支付交易会话标识后再按Native、JSAPI、APP等不同场景生成交易串调起支付。

入参：

/**
     * @author zzw
     * @date 2023/4/1 15:51
     * @description TODO 微信WxPayConfig配置
     */
    @Data
    public class PayVo {
        
        private String description; // 商品描述
        private String out_trade_no; // 商户订单号
        private String time_expire; // 订单失效时间
        private String attach; // 附加数据
        private String notify_url; // 回调
        private String openid; // 用户标识
        private String total; // 总金额
    }

预支付订单业务逻辑层

/**
         * 电子处方订单支付接口
         * @param payVo
         * @return
         */
        @Override
        public String payPrescription(PayVo payVo) {
        
            try {
        
                String errorString = null;
                String errorCode = null;
                String resXml = null;
                String nonce_str = WXPayUtil.generateNonceStr();
                JSONArray json = null;
                Map map = null;
                SortedMap<Object, Object> orderMap = new TreeMap<Object, Object>();
                /*-----  1.生成预支付订单需要的的package数据-----*/
                SortedMap<Object, Object> packageParams = new TreeMap<Object, Object>();
                // mchid直连商户号、wxappid应用ID、paysuccesscallback通知地址 都需要从程序内部获取，从而保证支付的安全性
                // paysuccesscallback 通知地址需要跟程序内部的地址一致
                packageParams.put("appid",wxappid); 
                packageParams.put("mch_id", mchid);
                packageParams.put("nonce_str", nonce_str);
                packageParams.put("notify_url", paysuccesscallback);
                packageParams.put("attach", payVo.getAttach());
                packageParams.put("openid", payVo.getOpenid());
                packageParams.put("out_trade_no", prescriptionPayVo.getOut_trade_no());
                packageParams.put("spbill_create_ip", WXPayUtil.localip());
                packageParams.put("total_fee",
                		   com.cn.ih.java.main.utils.Utils.getFee(payVo.getTotal()));
                packageParams.put("trade_type", "JSAPI");
                packageParams.put("fee_type", "CNY");
                packageParams.put("body", prescriptionPayVo.getDescription());
                packageParams.put("sign_type", "MD5");
                /*----2.根据package生成签名sign---- */
                String sign = PayForUtil.createSign("UTF-8", packageParams, selfkey);
                packageParams.put("sign", sign);
                logger.info("###signWX" + sign);
                String requestXML = PayForUtil.getRequestXml(packageParams);
                logger.info("###requestXML" + requestXML);
                resXml = WxHttpUtil.postData("https://api.mch.weixin.qq.com/pay/unifiedorder",requestXML);
                logger.info("###resXml" + resXml);
                if (null == resXml || "".equals(resXml)) {
        
                    errorString = "接口异常！返回数据为空，请检查接口是否可用；接口地址：https://api.mch.weixin.qq.com/pay/unifiedorder" ;
                    resXml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?> <xml> <return_code>" + "fail"
                            + "</return_code><return_msg>" + errorString + "</return_msg></xml> ";
                    logger.info("###" + errorString);
                    orderMap.put("ResultCode", "-1");
                    orderMap.put("ErrorMsg", "执行失败。");
                    json = JSONArray.fromObject(orderMap);
                } else {
        
                    try {
        
                        map = XMLUtil.doXMLParse(resXml);
                        String return_code = (String) map.get("return_code");
                        System.out.println(return_code);
                        String timestamp = String.valueOf(System.currentTimeMillis() / 1000);
                        String nonceStr = String.valueOf(System.currentTimeMillis());
                        orderMap.put("appId", sysConfig.getWxappid());
                        // 支付签名时间戳，注意微信jssdk中的所有使用timestamp字段均为小写。但最新版的支付后台生成签名使用的timeStamp字段名需大写其中的S字符
                        orderMap.put("timeStamp", timestamp);
                        orderMap.put("nonceStr", nonceStr);
                        logger.info("###nonceStr" + nonceStr);
                        orderMap.put("package", "prepay_id=" + map.get("prepay_id"));
                        orderMap.put("signType", "MD5");
                        String sign1 = PayForUtil.createSign("UTF-8", orderMap, selfkey);
                        orderMap.put("paySign", sign1);
                        orderMap.put("resCode", return_code);
                        logger.info("###sign" + map.get("sign"));
                        json = JSONArray.fromObject(orderMap);
                    } catch (JDOMException e) {
        
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    } catch (IOException e) {
        
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
                logger.info("###调用JSAPI预支付下单接口需要返回的参数" + json.toString());
                return json.toString();
            }catch(Exception e) {
        
                e.printStackTrace();
                return super.errorResult(e.getMessage());
            }

##### 5. 支付成功回调 #####

@ApiOperation(value = "支付成功回调")
        @RequestMapping(value="/paySucessCallMethod")
        public void paySuccessCallMethod(HttpServletRequest req, HttpServletResponse response){
        
            logger.info("========== 开始处理订单支付回调通知  ==========");
            String resultStr = null;
            String str = null;
            InputStream inputStream;
            StringBuffer sb = new StringBuffer();
            try {
        
                inputStream = req.getInputStream();
                String s;
                BufferedReader in = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"));
                while ((s = in.readLine()) != null) {
        
                    sb.append(s);
                }
                in.close();
                inputStream.close();
                // 解析xml成map
                Map<String, String> m = new HashMap<String, String>();
                m = XMLUtil.doXMLParse(sb.toString());
                // 过滤空设置TreeMap,扫码
                SortedMap<Object, Object> packageParams = new TreeMap<Object, Object>();
                Iterator<String> it = m.keySet().iterator();
                while (it.hasNext()) {
        
                    String parameter = it.next();
                    String parameterValue = m.get(parameter);
                    String v = "";
                    if (null != parameterValue) {
        
                        v = parameterValue.trim();
                    }
                    packageParams.put(parameter, v);
                }
                // 微信支付的api密钥
                String key = privatekey;
                logger.info("微信支付返回回来的参数：" + packageParams);
                String return_code = (String) packageParams.get("return_code");
                String result_code = (String) packageParams.get("result_code");
                DrugOrder drugOrder = null;
                // 判断签名是否正确
                if (PayForUtil.isTenpaySign("UTF-8", packageParams, key)) {
        
                    // -------------------------------
                    // 处理业务开始
                    // --------------------------
                    String resXml = "";
                    if (StrKit.notBlank(return_code) && StrKit.notBlank(result_code)
                            && return_code.equalsIgnoreCase("SUCCESS") && result_code.equalsIgnoreCase("SUCCESS")) {
        
                        // 支付成功
                        // 执行自己的业务逻辑
                        // 声明日志插入结果对象
                        String outTradeNo = ((String) packageParams.get("out_trade_no"));
                        logger.info("#########################开始校验订单号："+outTradeNo+"是否存在" );
                        Order order = orderPayRepository.findOrderPayByOutTradeNo(outTradeNo);
                        if(!StringUtils.isEmpty(order)) {
        
                            Order order  = order;
                            // 非第一次回调，已经成功生成订单，直接返回结果就可以了
                            /
                            // 执行自己业务逻辑结束
                            logger.info("给微信回调返回成功");
                            // 通知微信异步成功不然会一直通知后台八次之后交易失败
                            resXml = "<xml>" + "<return_code><![CDATA[SUCCESS]]></return_code>"
                                    + "<return_msg><![CDATA[OK]]></return_msg>" + "</xml> ";
                        }else {
        
                            //第一次回调
                            // **************************1.流水表插入*******************************//
                            logger.info("###流水表插入开始");
                            logger.info("###流水表插入开始packageParams：",packageParams);
    						
                            /* 执行相关业务逻辑，支付成功，生成支付订单 */
                            
                            logger.info("###流水表插入结束");
                            // 执行自己业务逻辑结束
                            logger.info("给微信回调返回成功");
                            // 通知微信异步成功不然会一直通知后台八次之后交易失败
                            resXml = "<xml>" + "<return_code><![CDATA[SUCCESS]]></return_code>"
                                    + "<return_msg><![CDATA[OK]]></return_msg>" + "</xml> ";
                       }
                    } else {
        
                        logger.info("支付失败,错误信息：" + packageParams.get("err_code"));
                        resXml = "<xml>" + "<return_code><![CDATA[FAIL]]></return_code>"
                                + "<return_msg><![CDATA[报文为空]]></return_msg>" + "</xml> ";
                    }
                    // ------------------------------
                    // 处理业务完毕
                    // ------------------------------
                    BufferedOutputStream out = new BufferedOutputStream(response.getOutputStream());
                    out.write(resXml.getBytes());
                    out.flush();
                    out.close();
                } else {
        
                    logger.info("通知签名验证失败");
                }
            } catch (Exception e) {
        
                // TODO Auto-generated catch block
                e.printStackTrace();
                TransactionAspectSupport.currentTransactionStatus().setRollbackOnly();
            }
            logger.info("==========结束处理处方支付回调通知==========");
        }

#### 2、微信小程序退款 ####

当交易发生之后一年内，由于买家或者卖家的原因需要退款时，卖家可以通过退款接口将支付金额退还给买家，微信支付将在收到退款请求并且验证成功之后，将支付款按原路退还至买家账号上。

##### 前提 #####

（1）微信退款所需要的配置! 退款只需要证书即可。微信退款需要证书：资金发生变化需要证书。支付接口不需要。点击证书使用。

按照步骤：下载证书。

（2）使用API证书

◆ apiclient\_cert.p12是商户证书文件，除PHP外的开发均使用此证书文件。  
◆ 商户如果使用.NET环境开发，请确认Framework版本大于2.0，必须在操作系统上双击安装证书apiclient\_cert.p12后才能被正常调用。  
◆ API证书调用或安装需要使用到密码，该密码的值为微信商户号（mch\_id）  
（3）API证书安全

1.证书文件不能放在web服务器虚拟目录，应放在有访问权限控制的目录中，防止被他人下载；  
2.建议将证书文件名改为复杂且不容易猜测的文件名；  
3.商户服务器要做好病毒和木马防护工作，不被非法侵入者窃取证书文件。

证书相关API：[https://blog.csdn.net/liyanlei5858/article/details/120021692][https_blog.csdn.net_liyanlei5858_article_details_120021692]

##### 注意： #####

1、交易时间超过一年的订单无法提交退款

2、微信支付退款支持单笔交易分多次退款（不超50次），多次退款需要提交原支付订单的商户订单号和设置不同的退款单号。申请退款总金额不能超过订单金额。 一笔退款失败后重新提交，请不要更换退款单号，请使用原商户退款单号

3、错误或无效请求频率限制：6qps，即每秒钟异常或错误的退款申请请求不超过6次

4、每个支付订单的部分退款次数不能超过50次

5、如果同一个用户有多笔退款，建议分不同批次进行退款，避免并发退款导致退款失败

6、申请退款接口的返回仅代表业务的受理情况，具体退款是否成功，需要通过退款查询接口获取结果

7、一个月之前的订单申请退款频率限制为：5000/min

8、同一笔订单多次退款的请求需相隔1分钟

##### 1. 编写退款相关工具类 #####

public class PayConfig implements WXPayConfig {
        
       private byte[] certData;
    
        /**
         * 微信退款所需要的配置! 退款只需要证书即可。
         * @throws Exception
         */
        public PayConfig() throws Exception {
        
            File file = new File(WxPayConstant.getPrivateppath());
            InputStream certStream = new FileInputStream(file);
            this.certData = new byte[(int) file.length()];
            certStream.read(this.certData);
            certStream.close();
        }
    
        @Override
        public String getAppID() {
        
            return WxPayConstant.getWxappid();  //appid
        }
    
        public String getAPPSECRET(){
        
            return WxPayConstant.getAppsecret();  //appSecret
        }
    
        @Override
        public String getMchID() {
        
            return WxPayConstant.getMchid();   //商户号id
        }
    
        @Override
        public String getKey() {
        
            return WxPayConstant.getPrivatekey();  //支付API密钥
        }
        @Override
        public InputStream getCertStream() {
        
            ByteArrayInputStream certBis = new ByteArrayInputStream(this.certData);
            return certBis;
        }
    
        @Override
        public int getHttpConnectTimeoutMs() {
        
            return 8000;
        }
    
        @Override
        public int getHttpReadTimeoutMs() {
        
            return 10000;
        }
    }

##### 2. 退款代码 #####

@Override
    public String refund(String transaction_id) {
        
        try {
        
            logger.info("#############################################执行微信支付退款接口refund方法开始");
            
           /* 执行微信小程序退款相关业务逻辑 */
            
            logger.info("==========================微信退款开始!!========================");
            Order order = orderRepository.findOrderByTransactionId(transaction_id);
            Map<String,String> data = new HashMap<String,String>();
            Integer pay = order.getTotalFee();
            OrderRefund orderRefund = orderRefundRepository.findOrderRefundByTransactionId(transaction_id);
            if (!ObjectUtils.isEmpty(drugOrderRefund)){
        
                logger.info("==========================此订单号对应的退款表已存在，重新执行退款操作!!========================"+orderRefund.toString());
                data.put("out_refund_no" , orderRefund.getOutRefundNo());
            }else {
        
                String out_refund_no = UUIDHexGenerator.createTradeNo();
                data.put("out_refund_no" , out_refund_no);
            }
    //            data.put("notify_url", null); // 根据自己的需求决定需要回调地址
            data.put("transaction_id" , transaction_id);
            data.put("total_fee" , String.valueOf(pay));
            data.put("refund_fee" , String.valueOf(pay));
            PayConfig config = new PayConfig();
            WXPay wxpay = new WXPay(config);
            data.put("appid" , appid);
            data.put("mch_id" , mch_id);
            data.put("nonce_str" , WXPayUtil.generateNonceStr());
            data.put("sign" , MD5Util.getSign(data));
            Map<String,String> resp = wxpay.refund(data);//获取微信退款返回的结果
            logger.info("微信返回信息:\n" + resp);
            String return_code = resp.get("return_code");   // 返回状态码
            String return_msg = resp.get("return_msg");     // 返回信息
            // 不管有没有退款成功，都要保存到退款表，如果退款成功，则删除支付表，如果退款失败，则退款表状态为失败
            logger.info("####################################################################流水表插入开始");
            OrderRefund orderRefund=new OrderRefund();
            List<OrderRefund> orderRefundList = orderRefundRepository.findOrderRefundByOutRefundNo(order.getOutTradeNo());
            if (CollectionUtils.isEmpty(orderRefundList)) {
        
            
            	//保存退款信息
    
                logger.info("#############################################################流水表对象赋值操作结束");
                // 调用service，插入日志表
                logger.info("#######################################################调用service，插入流水表开始");
                if("SUCCESS".equals(return_code)){
        
                	String result_code = resp.get("result_code");       //业务结果
                    String err_code_des = resp.get("err_code_des");     //错误代码描述
                    if("SUCCESS".equals(result_code)){
        
                    
                    	// 执行退款相关业务逻辑
                    	
    					logger.info("####################################################################流水表插入结束");
                        // 执行自己业务逻辑结束
                        logger.info("#####################################################################退款成功");
    				}else{
        
                            // 退款失败
                    }
    			}else{
        
                         // 退款失败
                }
                OrderRefund saveAndFlush = orderRefundRepository.saveAndFlush(orderRefund);
                logger.info("#####################################################################执行退款回调结束，退款表type: "+saveAndFlush.getType());
    		}
                resMap.put("timestamp", TimeHelper.getCurrentTime());
                String results = JsonHelper.parserMap(resMap);
                return results;
    	} catch (Exception e) {
        
        	e.printStackTrace();
    		return super.errorResult(e.getMessage());
    	}
    }

[https_pay.weixin.qq.com_wiki_doc_apiv3_open_pay_chapter1_1_1.shtml]: https://pay.weixin.qq.com/wiki/doc/apiv3/open/pay/chapter1_1_1.shtml
[https_pay.weixin.qq.com_wiki_doc_apiv3_apis_chapter3_1_9.shtml]: https://pay.weixin.qq.com/wiki/doc/apiv3/apis/chapter3_1_9.shtml
[img-JNr92RdW-1683010524685_E_PRD_Images_image-20230502113439837.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/22/a389b78cb8c84001b4e772044c7a4b0f.png
[https_blog.csdn.net_liyanlei5858_article_details_120021692]: https://blog.csdn.net/liyanlei5858/article/details/120021692