微信支付前的准备

微信支付退款功能需要证书，需要在微信支付平台的账号管理–>api安全中申请证书。

后台开发

话不多说，直接上代码吧，如果想细了解的请看官方文档
微信退款
1.实体类

  @ApiModel("微信退款实体类")
@Data
public class RefundDomain {/** orderId       商户订单号* */@JsonProperty(value = "orderId")@ApiModelProperty(value = "商户订单号",required=true)private String orderId;/** totalFee      订单金额/退款金额 也可以分为两个字段，退款金额不能大于订单金额* */@JsonProperty(value = "money")@ApiModelProperty(value = "订单金额/退款金额",required=true)private Double money;/** refundAccount 退款资金来源（默认传 "REFUND_SOURCE_UNSETTLED_FUNDS"）* */@JsonProperty(value = "refundAccount")@ApiModelProperty(value = "退款资金来源",required=false)private String refundAccount = "REFUND_SOURCE_UNSETTLED_FUNDS";
}

2. 控制层

    /*** 申请退款*/@ApiOperation(value="微信支付退款", notes="微信支付退款功能，前端传用户支付的金额以及当前用户退款的订单号")@PostMapping("/refund")public Map<String, String> refund(@RequestBody RefundDomain refundDomain) {System.out.println("money-------->:"+refundDomain.getMoney()); System.out.println("OrderId-------->:"+refundDomain.getOrderId());System.out.println("getRefundAccount-------->:"+refundDomain.getRefundAccount());// 生成唯一退款订单号Integer out_trade_no = (int) (System.currentTimeMillis() / 1000 + 970516);// 获取退款的金额 微信支付中的金额必须为正整数，所以需要把小数去掉。Double money = refundDomain.getMoney();Integer total_fee = money.intValue();SortedMap<String, Object> params = new TreeMap<String, Object>();params.put("appid", Parm.APPID); // 微信分配的小程序IDparams.put("mch_id", Parm.MCH_ID); // 微信支付分配的商务号params.put("nonce_str", randomString); // 随机字符串，不长于32位。params.put("out_trade_no", refundDomain.getOrderId()); //商户订单号和微信订单号二选一(我这里选的是商户订单号)params.put("out_refund_no", out_trade_no); // 商户退款单号params.put("total_fee", total_fee); // 订单金额params.put("refund_fee", total_fee); // 退款金额params.put("refund_account", refundDomain.getRefundAccount()); // 退款资金来源params.put("sign_type", "MD5"); // 签名类型String preStr = PayCommonUtil.createLinkString(params);//签名算法String sign = (PayCommonUtil.sign(preStr, Parm.KEY, "utf-8")).toUpperCase();System.out.println("sign-------->:"+sign);params.put("sign", sign);Map<String, String> map = new HashMap<>();try {System.out.println("params-------->:"+params);String xml = PayCommonUtil.getRequestXml(params);System.out.println("xml-------->:"+xml);String xmlStr = PayCommonUtil.doRefund("https://api.mch.weixin.qq.com/secapi/pay/refund", xml);System.out.println("xmlStr-------->:"+xmlStr);map = PayCommonUtil.doXMLParse(xmlStr);} catch (Exception e) {}return map;}

3.微信常量类

package com.studies.wx.util;import org.springframework.stereotype.Component;/*** @Description: 微信常量类*/
@Component
public class Parm {/*** 微信接入token，自定义但是一定要与公众平台上的保持一致*/public static final String TOKEN = "微信公众号平台中设置的，小程序不需要";public static final String APPID = "微信公众号或者小程序平台中开发者模式里面的";public static final String APPSECRET = "微信公众号或者小程序平台中开发者模式里面的";public static final String REDIRECT_URI = "http://localhost:8090/PcText（随意写的）";public static byte [] certData;/** 商务号api秘银* */public static String KEY = "微信支付平台中的秘银";/** 微信商务号* */public static String MCH_ID = "微信支付平台中给的商务号";/*** EncodingAESKey 公众平台上面自己填写的43位EncodingAESKey(服务号的)*/public static final String EncodingAESKey = "自己填写的";/*** 获取access_token的接口地址（GET） 限200（次/天）*/public static final String ACCESS_TOKEN_URL = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=APPID&secret=APPSECRET";/*** 获取JS_SDK_TICKET*/public static final String JS_SDK_TICKET_URL = "https://api.weixin.qq.com/cgi-bin/ticket/getticket?access_token=ACCESS_TOKEN&type=jsapi";/*** 获取网页授权的access_token的接口地址*/public static final String OAUTH2_ACCESS_TOKEN_URL = "https://api.weixin.qq.com/sns/oauth2/access_token?appid=APPID&secret=SECRET&code=CODE&grant_type=authorization_code";/*** 自定义菜单删除接口*/public static final String MENU_DELETE_URL = "https://api.weixin.qq.com/cgi-bin/menu/delete?access_token=ACCESS_TOKEN";/*** 自定义菜单的创建接口*/public static final String MENU_CREATE_URL = "https://api.weixin.qq.com/cgi-bin/menu/create?access_token=ACCESS_TOKEN";/*** 自定义菜单的查询接口*/public static final String MENU_GET_URL = "https://api.weixin.qq.com/cgi-bin/menu/get?access_token=ACCESS_TOKEN";/*** 客服接口-发消息接口*/public static final String CUSTOM_SERVICE_URL = "https://api.weixin.qq.com/cgi-bin/message/custom/send?access_token=ACCESS_TOKEN";/*** 发送模板消息接口*/public static final String SEND_TEMPLATE_URL = "https://api.weixin.qq.com/cgi-bin/message/template/send?access_token=ACCESS_TOKEN";/*** 创建标签接口** @Method :POST*/public static final String USE_TAG_CREATE_URL = "https://api.weixin.qq.com/cgi-bin/tags/create?access_token=ACCESS_TOKEN";/*** 获取用户身上的标签** @Method:POST*/public static final String GET_INUSER_TAG_URL = "https://api.weixin.qq.com/cgi-bin/tags/getidlist?access_token=ACCESS_TOKEN";/*** 批量为用户取消标签** @Method:POST*/public static final String UNTAGGING_USER_BATCH_URL = "https://api.weixin.qq.com/cgi-bin/tags/members/batchuntagging?access_token=ACCESS_TOKEN";/*** 创建个性化菜单** @Method :POST*/public static final String CREATE_PERSONALIZED_MENU_URL = "https://api.weixin.qq.com/cgi-bin/menu/addconditional?access_token=ACCESS_TOKEN";/*** 删除个性化菜单** @Method:*/public static final String DELETE_PERSONAL_MENU_URL = "https://api.weixin.qq.com/cgi-bin/menu/delconditional?access_token=ACCESS_TOKEN";/*** 给用户打标签的姐接口*/public static final String CREATE_USERTAG_URL = "https://api.weixin.qq.com/cgi-bin/tags/members/batchtagging?access_token=ACCESS_TOKEN";/*** 网页授权获取用户详细信息的的接口*/public static final String GET_USERINFO_URL = "https://api.weixin.qq.com/sns/userinfo?access_token=ACCESS_TOKEN&openid=OPENID&lang=zh_CN";/*** openid获取用户的基本信息的接口*/public static final String OPENID_USERINFO_URL = "https://api.weixin.qq.com/cgi-bin/user/info?access_token=ACCESS_TOKEN&openid=OPENID&lang=zh_CN";}

4.工具类

   public class PayCommonUtil {//微信参数配置public static String API_KEY = Parm.KEY;//随机字符串生成public static String getRandomString(int length) { //length表示生成字符串的长度String base = "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";Random random = new Random();StringBuffer sb = new StringBuffer();for (int i = 0; i < length; i++) {int number = random.nextInt(base.length());sb.append(base.charAt(number));}return sb.toString();}//请求xml组装public static String getRequestXml(SortedMap<String, 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 key = (String) entry.getKey();Object value = entry.getValue();if ("attach".equalsIgnoreCase(key) || "body".equalsIgnoreCase(key) || "sign".equalsIgnoreCase(key)) {sb.append("<" + key + ">" + "<![CDATA[" + value + "]]></" + key + ">");} else {sb.append("<" + key + ">" + value + "</" + key + ">");}}sb.append("</xml>");return sb.toString();}//xml解析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 = getChildrenText(children);}m.put(k, v);}//关闭流in.close();return m;}//生成签名public static String createSign(String characterEncoding, SortedMap<String, Object> parameters) {StringBuffer sb = new StringBuffer();Set es = parameters.entrySet();Iterator it = es.iterator();while (it.hasNext()) {Map.Entry entry = (Map.Entry) it.next();String k = (String) entry.getKey();Object v = entry.getValue();if (null != v && !"".equals(v)&& !"sign".equals(k) && !"key".equals(k)) {sb.append(k + "=" + v + "&");}}sb.append("key=" + API_KEY);System.out.println(sb.toString());String sign = MD5Util.MD5Encode(sb.toString(), characterEncoding).toUpperCase();return sign;}/*** 签名字符串** @param text          需要签名的字符串* @param key           密钥* @param input_charset 编码格式* @return 签名结果*/public static String sign(String text, String key, String input_charset) {text = text + "&key=" + key;return DigestUtils.md5Hex(getContentBytes(text, input_charset));}private static byte[] getContentBytes(String content, String charset) {if (charset == null || "".equals(charset)) {return content.getBytes();}try {return content.getBytes(charset);} catch (UnsupportedEncodingException e) {throw new RuntimeException("MD5签名过程中出现错误,指定的编码集不对,您目前指定的编码集是:" + charset);}}/*** 验证回调签名** @return*/public static boolean isTenpaySign(Map<String, String> map) {String characterEncoding = "utf-8";String charset = "utf-8";String signFromAPIResponse = map.get("sign");if (signFromAPIResponse == null || signFromAPIResponse.equals("")) {System.out.println("API返回的数据签名数据不存在，有可能被第三方篡改!!!");return false;}System.out.println("服务器回包里面的签名是:" + signFromAPIResponse);//过滤空 设置 TreeMapSortedMap<String, String> packageParams = new TreeMap();for (String parameter : map.keySet()) {String parameterValue = map.get(parameter);String v = "";if (null != parameterValue) {v = parameterValue.trim();}packageParams.put(parameter, v);}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);//将API返回的数据根据用签名算法进行计算新的签名，用来跟API返回的签名进行比较//算出签名String resultSign = "";String tobesign = sb.toString();if (null == charset || "".equals(charset)) {resultSign = MD5Util.MD5Encode(tobesign, characterEncoding).toUpperCase();} else {try {resultSign = MD5Util.MD5Encode(tobesign, characterEncoding).toUpperCase();} catch (Exception e) {resultSign = MD5Util.MD5Encode(tobesign, characterEncoding).toUpperCase();}}String tenpaySign = ((String) packageParams.get("sign")).toUpperCase();return tenpaySign.equals(resultSign);}//请求方法public static String httpsRequest(String requestUrl, String requestMethod, String outputStr) {try {URL url = new URL(requestUrl);HttpURLConnection conn = (HttpURLConnection) url.openConnection();conn.setDoOutput(true);conn.setDoInput(true);conn.setUseCaches(false);// 设置请求方式（GET/POST）conn.setRequestMethod(requestMethod);conn.setRequestProperty("content-type", "application/x-www-form-urlencoded");// 当outputStr不为null时向输出流写数据if (null != outputStr) {OutputStream outputStream = conn.getOutputStream();// 注意编码格式outputStream.write(outputStr.getBytes("UTF-8"));outputStream.close();}// 从输入流读取返回内容InputStream inputStream = conn.getInputStream();InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "utf-8");BufferedReader bufferedReader = new BufferedReader(inputStreamReader);String str = null;StringBuffer buffer = new StringBuffer();while ((str = bufferedReader.readLine()) != null) {buffer.append(str);}// 释放资源bufferedReader.close();inputStreamReader.close();inputStream.close();inputStream = null;conn.disconnect();return buffer.toString();} catch (ConnectException ce) {System.out.println("连接超时：{}" + ce);} catch (Exception e) {System.out.println("https请求异常：{}" + e);}return null;}/*** 把数组所有元素排序，并按照“参数=参数值”的模式用“&”字符拼接成字符串** @param params 需要排序并参与字符拼接的参数组* @return 拼接后字符串*/public static String createLinkString(SortedMap<String, Object> params) {List<String> keys = new ArrayList<>(params.keySet());Collections.sort(keys);String preStr = "";for (int i = 0; i < keys.size(); i++) {String key = keys.get(i);String value = params.get(key).toString();if (i == keys.size() - 1) {// 拼接时，不包括最后一个&字符preStr = preStr + key + "=" + value;} else {preStr = preStr + key + "=" + value + "&";}}return preStr;}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(getChildrenText(list));}sb.append(value);sb.append("</" + name + ">");}}return sb.toString();}/*** 调用微信退款接口*/public static String doRefund(String url, String data) throws Exception {KeyStore keyStore = KeyStore.getInstance("PKCS12"); //证书格式try {InputStream certStream = Thread.currentThread().getContextClassLoader().getResourceAsStream("apiclient_cert.p12");System.out.println("certStream----->:"+certStream);Parm.certData = IOUtils.toByteArray(certStream);certStream.close();} catch (Exception e) {e.printStackTrace();}ByteArrayInputStream is = new ByteArrayInputStream(Parm.certData);try {keyStore.load(is, Parm.MCH_ID.toCharArray());} finally {is.close();}// Trust own CA and all self-signed certsSSLContext sslcontext = SSLContexts.custom().loadKeyMaterial(keyStore,Parm.MCH_ID.toCharArray()).build();// Allow TLSv1 protocol onlySSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslcontext,new String[]{"TLSv1"},null,SSLConnectionSocketFactory.BROWSER_COMPATIBLE_HOSTNAME_VERIFIER);CloseableHttpClient httpclient = HttpClients.custom().setSSLSocketFactory(sslsf).build();try {HttpPost httpost = new HttpPost(url); // 设置响应头信息httpost.addHeader("Connection", "keep-alive");httpost.addHeader("Accept", "*/*");httpost.addHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");httpost.addHeader("Host", "api.mch.weixin.qq.com");httpost.addHeader("X-Requested-With", "XMLHttpRequest");httpost.addHeader("Cache-Control", "max-age=0");httpost.addHeader("User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0) ");httpost.setEntity(new StringEntity(data, "UTF-8"));CloseableHttpResponse response = httpclient.execute(httpost);try {HttpEntity entity = response.getEntity();String jsonStr = EntityUtils.toString(response.getEntity(), "UTF-8");EntityUtils.consume(entity);return jsonStr;} finally {response.close();}} finally {httpclient.close();}}// 获取设备ippublic static String getRemoteHost(HttpServletRequest request) {String ip = request.getHeader("x-forwarded-for");if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {ip = request.getHeader("Proxy-Client-IP");}if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {ip = request.getHeader("WL-Proxy-Client-IP");}if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {ip = request.getRemoteAddr();}return ip.equals("0:0:0:0:0:0:0:1") ? "127.0.0.1" : ip;}
}

vue前端

// 微信退款let param = {orderId:this.data.out_trade_no, // 支付的商户订单号money:this.data.total_fee, // 用户支付的金额};console.log(param);// 前端我使用了axios接口统一管理模式，refundController后台接口refundController(param).then(ref =>{console.log(ref);// 如果退款成功 result_code 返回success，如果退款失败 result_code 返回fallif(ref.data.result_code === "SUCCESS"){uni.showToast({icon: 'none',title: "退款成功",duration: 2000})}else{uni.showToast({icon: 'none',title: ref.data.err_code_des, // 退款失败，err_code_des才会返回，退款成功则不会返回这个字段duration: 2000})}})

微信支付退款就到此结束了。