java 微信app支付

        log.info("生成微信app支付订单");
        String outTradeNo = IdWorker.get32UUID();//平台内部订单变化
		 BigDecimal amount = new BigDecimal(20);
        log.info("调用统一下单api");
        //调用统一下单api
        HttpPost httpPost = new HttpPost("https://api.mch.weixin.qq.com/v3/pay/transactions/app");
        //请求body参数
        Gson gson = new Gson();
        Map parmsMap = new HashMap<>();
        parmsMap.put("mchid", mchId);
        parmsMap.put("out_trade_no", outTradeNo);
        parmsMap.put("appid", appid);
        parmsMap.put("description", "本次下单");
        parmsMap.put("notify_url", "微信支付回调地址");//地址必须白名单,可外网访问
        Map amountMap = new HashMap();
        //微信亦分为单位调整为*100
        amountMap.put("total",amount.multiply(new BigDecimal("100")).intValue());
        amountMap.put("currency", "CNY");
        parmsMap.put("amount", amountMap);
        String jsonParams = gson.toJson(parmsMap);

        log.info("请求参数：" + jsonParams);
        StringEntity entity = new StringEntity(jsonParams, "utf-8");
        entity.setContentType("application/json");
        httpPost.setEntity(entity);
        httpPost.setHeader("Accept", "application/json");
        //完成签名并执行请求
        CloseableHttpResponse response = wxPayClient.execute(httpPost);
        try {
            String bodyAsString = EntityUtils.toString(response.getEntity());
            int statusCode = response.getStatusLine().getStatusCode();
            if (statusCode == 200) { //处理成功
                log.info("app下单成功,返回结果" + bodyAsString);
                //插入数据库
            } else if (statusCode == 204) { //处理成功，无返回Body
                log.info("成功");
            } else {
                log.info("app下单失败,响应码=" + statusCode + ",返回结果=" + bodyAsString);
                throw new IOException("request failed");
            }
            //响应结果
            HashMap<String, String> resultMap = gson.fromJson(bodyAsString, HashMap.class);
            String prepayId = resultMap.get("prepay_id");
            log.info("生成prepayId：" + prepayId);
            //appid 根据不同app适配 //privateKeyPath 商户私钥文件地址
            JSONObject jsonObject = WxAppPayTuneUp(prepayId, appid, mchId, privateKeyPath);
            log.info(jsonObject);
        } finally {
            response.close();
        }
		
		
		
		public static JSONObject WxAppPayTuneUp(String prepayId, String appId, String mchId, String privateKeyPath) throws Exception {
        if (StringUtils.isNotBlank(prepayId)) {
            long timestamp = System.currentTimeMillis() / 1000;
            String nonceStr = generateNonceStr();
            //加载签名
            String packageSign = sign(buildMessage(appId, timestamp, nonceStr, prepayId).getBytes(), private_key_path);
            JSONObject jsonObject = new JSONObject();
            jsonObject.put("appId", appId);
            jsonObject.put("prepayId", prepayId);
            jsonObject.put("timeStamp", timestamp);
            jsonObject.put("nonceStr", nonceStr);
            jsonObject.put("package", "Sign=WXPay");
            jsonObject.put("signType", "RSA");
            jsonObject.put("sign", packageSign);
            jsonObject.put("partnerId", mchId);
            return jsonObject;
        }
        return new JSONObject();
    }
	
	
	/**
     * 按照前端签名文档规范进行排序，\n是换行
     *
     * @param appId     appId
     * @param timestamp 时间
     * @param nonceStr  随机字符串
     * @param prepay_id prepay_id
     * @return
     */
    public static String buildMessage(String appId, long timestamp, String nonceStr, String prepay_id) {
        return appId + "\n" + timestamp + "\n" + nonceStr + "\n" + prepay_id + "\n";
    }
	
	public static String sign(byte[] message, String privateKeyPath) throws NoSuchAlgorithmException, SignatureException, IOException, InvalidKeyException {
        //签名方式
        Signature sign = Signature.getInstance("SHA256withRSA");
        //私钥
        sign.initSign(PemUtil.loadPrivateKey(new FileInputStream(privateKeyPath)));
        sign.update(message);

        return Base64.getEncoder().encodeToString(sign.sign());
    }

支付微信回调

 /**
     * 微信支付成功后.异步请求该接口
     *
     * @param request
     * @return
     * @throws IOException
     */
    @PostMapping("/weChatNotify")
    public String nativeNotity(HttpServletRequest request, HttpServletResponse response) throws Exception {
        Gson gson = new Gson();
        // 应答对象
        Map<String, String> map = new HashMap<>();
        // 处理通知参数
        String body = HttpUtils.readData(request);
        JSONObject jsonObject = JSONObject.parseObject(body);
        String eventType = (String) jsonObject.get("event_type");
        JSONObject resource = (JSONObject) jsonObject.get("resource");
        String associated_data = (String) resource.get("associated_data");
        String nonce = (String) resource.get("nonce");
        String ciphertext = (String) resource.get("ciphertext");
		String UUID = UUID.randomUUID().toString().replaceAll("-", "");
        AesUtil aesUtil = new AesUtil(UUID.getBytes());

        String s = aesUtil.decryptToString(associated_data.getBytes(), nonce.getBytes(), ciphertext);
        JSONObject jsonObject1 = JSONObject.parseObject(s);
        String outTradeNo = jsonObject1.getString("out_trade_no");
        try {
            //如果微信返回状态为TRANSACTION.SUCCESS
            if (eventType.equals("TRANSACTION.SUCCESS")) {
                response.setStatus(200);
                map.put("code", "TRANSACTION.SUCCESS");
                map.put("message", "成功");
            }

        } catch (Exception e) {
            throw new RuntimeException("更新工友豆数量失败!");
        }
        map.put("code", "ERROR");
        map.put("message", "失败");
        return gson.toJson(map);
    }


  /**
     * 将通知参数转化为字符串
     * @param request
     * @return
     */
    public static String readData(HttpServletRequest request) {
        BufferedReader br = null;
        try {
            StringBuilder result = new StringBuilder();
            br = request.getReader();
            for (String line; (line = br.readLine()) != null; ) {
                if (result.length() > 0) {
                    result.append("\n");
                }
                result.append(line);
            }
            return result.toString();
        } catch (IOException e) {
            throw new RuntimeException(e);
        } finally {
            if (br != null) {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }