需求

在微信小程序中实现一个提现功能 ，提现的钱其实来自系统中的其他功能。

当然这个功能，需要一个微信支付的商户号，并且账户中需要有充足的余额。

前期准备

1、登录微信商户平台官网：微信支付 - 中国领先的第三方支付平台 ｜ 微信支付提供安全快捷的支付方式 (qq.com)

2、找到产品中心的企业付款到零钱，并开通企业付款到零钱功能

3、找到AppID账号管理，添加关联AppID

4、将微信商户号和小程序进行绑定

5、申请API证书和APIv2密钥，妥善保存，后面会使用

注：API证书文件的后缀是.p12

6、获取商户号

代码实现（SpringBoot）

1、引入相关官方依赖

<dependency><groupId>com.github.wxpay</groupId><artifactId>wxpay-sdk</artifactId><version>0.0.3</version></dependency>

2、在yaml文件添加配置

withDraw:apiKey: xxxxxxxx mchid: xxxxxx mch_appid: xxxxxxxxx //此路径代表是在项目的resouce根目录 certPath: /xxxxxxxx.p12 count: 10 quota: 200

3、编写配置类

@Componentpublic class WithDrawConfig implements WXPayConfig {//从yaml注入配置@Value("${withDraw.mch_appid}")private String mch_appid;@Value("${withDraw.apiKey}")private String apiKey;@Value("${withDraw.mchid}")private String mchid;@Value("${withDraw.certPath}")private String certPath;@Overridepublic String getAppID() {return mch_appid;}@Overridepublic String getMchID() {return mchid;}@Overridepublic String getKey() {return apiKey;}@Overridepublic InputStream getCertStream() {//获取证书,证书建议放到resource目录下return this.getClass().getResourceAsStream(certPath);}@Overridepublic int getHttpConnectTimeoutMs() {return 8000;}@Overridepublic int getHttpReadTimeoutMs() {return 10000;}}

4、编写提现工具类

@Slf4j@Component@RequiredArgsConstructorpublic class WithDrawUtils {@Value("${withDraw.mch_appid}")private String mch_appid;@Value("${withDraw.mchid}")private String mchid;@Value("${withDraw.apiKey}")private String apiKey;private final WithDrawConfig withDrawConfig;//生成订单号日期时间+随机字符public String getOrderNumber() {SimpleDateFormat date = new SimpleDateFormat("yyyyMMddHHmmss");return date.format(new Date()) + RandomStringUtils.randomNumeric(4);}public Map<String, String> fillRequest(Map<String, String> reqData) throws Exception {reqData.put("mch_appid", mch_appid);reqData.put("mchid", mchid);reqData.put("nonce_str", WXPayUtil.generateNonceStr().toUpperCase());reqData.put("sign", WXPayUtil.generateSignature(reqData, apiKey, WXPayConstants.SignType.MD5));return reqData;}public String getMd5ByString(String str) {StringBuilder hexString = new StringBuilder();try {MessageDigest mdTemp = MessageDigest.getInstance("MD5");mdTemp.update(str.getBytes());byte[] hash = mdTemp.digest();for (byte b : hash) {if ((0xff & b) < 0x10) {hexString.append("0").append(Integer.toHexString((0xFF & b)));} else {hexString.append(Integer.toHexString(0xFF & b));}}} catch (NoSuchAlgorithmException e) {e.printStackTrace();}return hexString.toString();}/** * 将对象直接转换成String类型的 XML输出 * * @param obj * @return */public String convertToXml(Object obj) {// 创建输出流StringWriter sw = new StringWriter();try {// 利用jdk中自带的转换类实现JAXBContext context = JAXBContext.newInstance(obj.getClass());Marshaller marshaller = context.createMarshaller();// 格式化xml输出的格式marshaller.setProperty(Marshaller.JAXB_FRAGMENT,Boolean.TRUE);// 将对象转换成输出流形式的xmlmarshaller.marshal(obj, sw);} catch (JAXBException e) {e.printStackTrace();}return sw.toString();}public String getRestInstance(String url, String data) throws Exception {String UTF8 = "UTF-8";URL httpUrl = new URL(url);char[] password = mchid.toCharArray();//证书密码InputStream certStream = withDrawConfig.getCertStream();//获取证书的流KeyStore ks = KeyStore.getInstance("PKCS12");ks.load(certStream, password);// 实例化密钥库 & 初始化密钥工厂KeyManagerFactory kmf = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());kmf.init(ks, password);SSLContext sslContext = SSLContext.getInstance("TLS");sslContext.init(kmf.getKeyManagers(), (TrustManager[]) null, new SecureRandom());HttpsURLConnection.setDefaultSSLSocketFactory(sslContext.getSocketFactory());HttpURLConnection httpURLConnection = (HttpURLConnection) httpUrl.openConnection();httpURLConnection.setDoOutput(true);httpURLConnection.setRequestMethod("POST");httpURLConnection.setConnectTimeout(withDrawConfig.getHttpConnectTimeoutMs());httpURLConnection.setReadTimeout(withDrawConfig.getHttpReadTimeoutMs());httpURLConnection.connect();OutputStream outputStream = httpURLConnection.getOutputStream();outputStream.write(data.getBytes(UTF8));InputStream inputStream = httpURLConnection.getInputStream();BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, UTF8));StringBuilder stringBuffer = new StringBuilder();String line;while ((line = bufferedReader.readLine()) != null) {stringBuffer.append(line);}String resp = stringBuffer.toString();try {bufferedReader.close();} catch (IOException ignored) {}try {inputStream.close();} catch (IOException ignored) {}try {outputStream.close();} catch (IOException ignored) {}if (certStream != null) {try {certStream.close();} catch (IOException ignored) {}}return resp;}}

5、提现的业务实现

提现参数封装实体：WithDrawDTO

@XmlRootElement(name = "xml")@XmlAccessorType(XmlAccessType.FIELD)@Datapublic class WithDrawDTO implements Serializable {@ApiModelProperty(value = "申请商户号的appid或商户号绑定的appid")private String mch_appid;@ApiModelProperty(value = "微信支付分配的商户号")private String mchid;@ApiModelProperty(value = "随机字符串，不长于32位")private String nonce_str;@ApiModelProperty(value = "签名")private String sign;@ApiModelProperty(value = "商户订单号，需保持唯一性")private String partner_trade_no;@ApiModelProperty(value = "openid是微信用户在公众号appid下的唯一用户标识（appid不同，则获取到的openid就不同），可用于永久标记一个用户。")private String openid;@ApiModelProperty(value = "NO_CHECK：不校验真实姓名,FORCE_CHECK：强校验真实姓名")private String check_name;@ApiModelProperty(value = "收款用户真实姓名。如果check_name设置为FORCE_CHECK，则必填用户真实姓名,如需电子回单，需要传入收款用户姓名")private String re_user_name;@ApiModelProperty(value = "付款金额，单位为分")private Integer amount;@ApiModelProperty(value = "付款备注，必填。注意：备注中的敏感词会被转成字符*")private String desc;}

官方接口文档：【微信支付】付款开发者文档 (qq.com)

//开始提现，生成订单号String orderNumber = withDrawUtils.getOrderNumber();//自定义的将提现所需要的参数封装的实体类WithDrawDTO withDrawDTO = new WithDrawDTO();withDrawDTO.setPartner_trade_no(orderNumber);withDrawDTO.setDesc("xxxxx");withDrawDTO.setAmount(appletWithDrawDTO.getAmount());//此参数代表，开启真实姓名校验，也可以关闭，详看官方文档的参数说明withDrawDTO.setCheck_name("FORCE_CHECK");withDrawDTO.setRe_user_name(appletWithDrawDTO.getName());//微信小程序用户的openidwithDrawDTO.setOpenid(wxUser.getOpenid());Map<String, String> params = JSON.parseObject(JSON.toJSONString(withDrawDTO), new TypeReference<Map<String, String>>() {});params = withDrawUtils.fillRequest(params);withDrawDTO.setNonce_str(params.get("nonce_str"));withDrawDTO.setMchid(params.get("mchid"));withDrawDTO.setMch_appid(params.get("mch_appid"));withDrawDTO.setSign(params.get("sign"));String url = "https://api.mch.weixin.qq.com/mmpaymkttransfers/promotion/transfers";String post = withDrawUtils.getRestInstance(url, withDrawUtils.convertToXml(withDrawDTO));Map<String, String> result = WXPayUtil.xmlToMap(post);//result为调用接口之后的返回参数，可以根据返回参数判断是否成功WithDrawEnum resultEnum;if ("SUCCESS".equals(result.get("result_code"))) {//提现成功resultEnum = WithDrawEnum.fromText("SUCCESS");return resultEnum;} else {//提现失败resultEnum = WithDrawEnum.fromText(result.get("err_code"));throw new BadRequestException(resultEnum);}

6、提现返回错误代码的枚举类

@Getter@NoArgsConstructor@AllArgsConstructorpublic enum WithDrawEnum {SUCCESS(0, "提现成功"),FAIL(400, "提现失败，余额小于提现金额"),HANDLE_FRE(5000, "操作太频繁"),NO_AUTH(5001, "没有该接口权限"),AMOUNT_LIMIT(5002, "金额超限"),PARAM_ERROR(5003, "参数错误"),OPENID_ERROR(5004, "Openid错误"),SEND_FAILED(5005, "付款错误"),NOTENOUGH(5006, "余额不足"),SYSTEMERROR(5007, "系统繁忙，请稍后再试。"),NAME_MISMATCH(5008, "姓名校验出错"),SIGN_ERROR(5009, "签名错误"),XML_ERROR(5010, "发送内容出错"),FATAL_ERROR(5011, "两次发送参数不一致"),FREQ_LIMIT(5012, "超过频率限制，请稍后再试。"),MONEY_LIMIT(5013, "已经达到今日付款总额上限/已达到付款给此用户额度上限"),CA_ERROR(5014, "商户证书校验出错"),V2_ACCOUNT_SIMPLE_BAN(5015, "无法给未实名用户付款"),PARAM_IS_NOT_UTF8(5016, "发送参数中包含不规范字符"),SENDNUM_LIMIT(5017, "该用户今日付款次数超过限制, 如有需要请进入【微信支付商户平台-产品中心-付款到零钱-产品设置】进行修改"),RECV_ACCOUNT_NOT_ALLOWED(5018, "收款账户不在收款账户列表"),PAY_CHANNEL_NOT_ALLOWED(5019, "本商户号未配置此功能"),SEND_MONEY_LIMIT(5020, "已达到今日商户付款额度上限"),RECEIVED_MONEY_LIMIT(5021, "已达到今日付款给此用户额度上限");private int code;private String msg;public static WithDrawEnum fromText(String text) {if (text != null) {for (WithDrawEnum b : WithDrawEnum.values()) {if (text.equalsIgnoreCase(b.name())) {return b;}}}return null;}}

最后

微信相关接口的调用，主要还是要耐心看文档的说明，才能实现业务需求。