微信公众号-JSAPI支付（保姆级教程）

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微信公众号-JSAPI支付

1、微信公众号配置

2、微信支付配置

⑤添加支付域名配置

⑥暴露域名

⑦AppId账号设置-商户关联公众号

程序配置

主要流程及代码实现

 public static String getOpenId(String code) throws Exception { // 构建请求URL String requestUrl = "https://api.weixin..com/sns/oauth2/access_token?appid=" + APP_ID + "&secret=" + APP_SECRET + "&code=" + code + "&grant_type=authorization_code"; // 发送HTTP GET请求 URL url = new URL(requestUrl); HttpURLConnection connection = (HttpURLConnection) url.openConnection(); connection.setRequestMethod("GET"); int responseCode = connection.getResponseCode(); if (responseCode == HttpURLConnection.HTTP_OK) { // 请求成功 BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream())); StringBuilder response = new StringBuilder(); String line; while ((line = in.readLine()) != null) { response.append(line); } in.close(); // 解析JSON响应，获取openid String jsonResponse = response.toString(); JsonObject jsonObject = new Gson().fromJson(jsonResponse, JsonObject.class); String openid = jsonObject.get("openid").getAsString(); return openid; } else { throw new Exception("HTTP GET请求失败：" + responseCode); } 

②获取到openId后，构建请求参数

 log.info("code:{}", code); String openId = WXGetOpenIdUtil.getOpenId(code); //请求URL HttpPost httpPost = new HttpPost(WxPayJsApiConstant.JS_API_URL); // 请求body参数 WxPayJsApiAmountBO amount = new WxPayJsApiAmountBO(); amount.setTotal(1);//总金额 amount.setCurrency("CNY");//货币类型 WxPayPayerBO payer = new WxPayPayerBO(); payer.setOpenid(openId);//openId WxPayJsApiOrderBO request = new WxPayJsApiOrderBO(); request.setMchid(mchId);//商户号 String out_trade_no = DateUtil.format(new Date(), DatePattern.PURE_DATETIME_MS_PATTERN); request.setOut_trade_no(out_trade_no);//生成的订单号 request.setAttach("--非必填数据--");//附加信息 request.setAppid(appId);//appId request.setDescription("停车费用");//描述 request.setNotify_url(notifyUrl);//异步接收微信支付结果通知的回调地址 request.setAmount(amount);//订单金额信息：总金额 货币类型 request.setPayer(payer);//openId如何获取 StringEntity entity = new StringEntity(JSONUtil.toJsonStr(request), "utf-8"); entity.setContentType("application/json"); httpPost.setEntity(entity); httpPost.setHeader(WxPayJsApiHeaderConstant.HTTP_HEADER_ACCEPT, WxPayJsApiHeaderConstant.HTTP_HEADER_ACCEPT_VAL); 

其中initCloseableHttpClientV3方法为：读取resources下的apiclient_key.pem密钥文件 获取秘钥 构建请求信息

 / * 构造 - 通用CloseableHttpClient（定时更新平台证书功能） / protected CloseableHttpClient initCloseableHttpClientV3() throws IOException, HttpCodeException, GeneralSecurityException, NotFoundException { // 获取 - 秘钥证书信息 PrivateKey merchantPrivateKey = PemUtil.loadPrivateKey(new FileInputStream(WxPayJsApiHttpUtil.getResourcesPath() + "apiclient_key.pem")); // 获取 - 证书管理器实例 CertificatesManager certificatesManager = CertificatesManager.getInstance(); // 操作 - 向证书管理器增加需要自动更新平台证书的商户信息 certificatesManager.putMerchant(mchId, new WechatPay2Credentials(mchId, new PrivateKeySigner(mchSerialNo, merchantPrivateKey)), apiV3Key.getBytes(StandardCharsets.UTF_8)); // ... 若有多个商户号，可继续调用putMerchant添加商户信息 // 操作 - 从证书管理器中获取verifier Verifier verifier = certificatesManager.getVerifier(mchId); WechatPayHttpClientBuilder builder = WechatPayHttpClientBuilder.create() .withMerchant(mchId, mchSerialNo, merchantPrivateKey) .withValidator(new WechatPay2Validator(verifier)); // 构造通过WechatPayHttpClientBuilder构造的HttpClient，会自动的处理签名和验签，并进行证书自动更新 return builder.build(); } 

构建完成后，调用微信JSAPI下单地址httpPost： https://api.mch.weixin..com/v3/pay/transactions/jsapi

 // 构建 - 请求信息 CloseableHttpClient closeableHttpClient = initCloseableHttpClientV3(); // 操作 - 完成请求 CloseableHttpResponse response = closeableHttpClient.execute(httpPost); String bodyAsString = EntityUtils.toString(response.getEntity()); System.out.println(bodyAsString); try { int statusCode = response.getStatusLine().getStatusCode(); if (statusCode == 200) { JsonObject jsonObject = new Gson().fromJson(bodyAsString, JsonObject.class); //获取微信支付中的预支付id String prepayId = jsonObject.get("prepay_id").getAsString(); System.out.println("success,return body = " + EntityUtils.toString(response.getEntity()) + "prepay_id = " + prepayId); } else if (statusCode == 204) { System.out.println("success"); } else { System.out.println("failed,resp code = " + statusCode + ",return body = " + EntityUtils.toString(response.getEntity())); throw new IOException("request failed"); } } finally { response.close(); closeableHttpClient.close(); } // 构造 - 响应信息 prepay_id WxPayJsApiPreVO result = convertWxPayJsApiPreInfo((String) JSONUtil.parseObj(bodyAsString).get(WxPayJsApiOtherConstant.HTTP_OTHER_PREPAY_ID)); System.out.println("result -> " + JSONUtil.toJsonStr(result)); return result; 

其中convertWxPayJsApiPreInfo方法获取JSAPI加密串，构造响应信息result

 protected WxPayJsApiPreVO convertWxPayJsApiPreInfo(String prepayId) throws Exception { logger.info("[开始]预支付信息-prepayId : {}", prepayId); // 构建 - 相关参数 String time = String.valueOf(System.currentTimeMillis() / 1000); String nonceStr = UUID.randomUUID().toString().replace("-", ""); String packageStr = StrUtil.format(WxPayJsApiConstant.SIGN_PACKAGE_STR, prepayId); // 构建 - 签名信息 ArrayList<String> list = new ArrayList<>(); list.add(appId); list.add(time); list.add(nonceStr); list.add(packageStr); // 操作 - 签名 String packageSign = wxPayJsApiSignUtil.signV3(WxPayJsApiSignUtil.buildSignMessage(list).getBytes()); // 构建 - 响应信息 WxPayJsApiPreVO result = new WxPayJsApiPreVO(); result.setWxAppId(appId); result.setWxTimeStamp(time); result.setWxNonceStr(nonceStr); result.setWxPackage(packageStr); result.setWxSignType(WxPayJsApiConstant.SIGN_TYPE); result.setWxPaySign(packageSign); logger.info("[结束]预支付信息-WxPayJsApiPreVO : {}", JSONUtil.toJsonStr(result)); return result; } 

1. function onBridgeReady() { 2. WeixinJSBridge.invoke('getBrandWCPayRequest', { 3. "appId": "xxx", //公众号ID，由商户传入 4. "timeStamp": "xxx", //时间戳，自1970年以来的秒数 5. "nonceStr": "xxx", //随机串 6. "package": "prepay_id=xxx", 7. "signType": "RSA", //微信签名方式： 8. "paySign": "xxx" //微信签名 9. }, 10. function(res) { 11. if (res.err_msg == "get_brand_wcpay_request:ok") { 12. // 使用以上方式判断前端返回,微信团队郑重提示： 13. //res.err_msg将在用户支付成功后返回ok，但并不保证它绝对可靠。 14. } 15. }); 16. } 

④微信回调 支付后微信向改地址发送支付结果通知

1. //读取微信回调的内容 2. InputStream inStream = request.getInputStream(); 3. ByteArrayOutputStream outSteam = new ByteArrayOutputStream(); 4. byte[] buffer = new byte[1024]; 5. int len; 6. while ((len = inStream.read(buffer)) != -1) { 7. outSteam.write(buffer, 0, len); 8. } 9. String resultXml = new String(outSteam.toByteArray(), "utf-8"); 10. outSteam.close(); 11. inStream.close(); 12. //xml转成map 13. Map<String, String> params = WXPayUtil.xmlToMap(resultXml); 14. Map<String, String> return_data = new HashMap<>(); //返回给微信信息 15. if ("SUCCESS".equals(params.get("return_code"))) { //返回成功 付款成功 16. String outTradeNo = params.get("out_trade_no"); //返回的商户订单号 17. Integer totalFee = Integer.parseInt(params.get("total_fee")); //总金额 18. ParkingBasicInfo parkingBasicInfo = parkingBasicInfoService.lambdaQuery().eq(ParkingBasicInfo::getOutTradeNo, outTradeNo).one(); 19. if (ObjectUtil.isNotEmpty(parkingBasicInfo)) { 20. if (totalFee.equals(parkingBasicInfo.getPayMoney())) { 21. String paymentTime = params.get("time_end"); //支付完成时间 22. //发票表添加支付时间 23. String transactionId = params.get("transaction_id"); //微信支付订单号 24. //支付成功后修改订单信息 paymentTime transactionId微信支付订单号 25. } 26. } 27. //正确返回给微信 28. return_data.put("return_code", "SUCCESS"); 29. return_data.put("return_msg", "OK"); 30. return WXPayUtil.mapToXml(return_data); 31. } 32. // 支付失败 33. return_data.put("return_code", "FAIL"); 34. return_data.put("return_msg", "return_code不正确"); 35. return WXPayUtil.mapToXml(return_data);