springboot微信小程序支付

今天有项目开发用到多个微信商户进行支付的场景，使用微信的SDK不太方便，以下大概使用了微信支付的示例仅供参考：

微信支付在请求接口时都要生成请求头，直接上代码：

    /**
     * 构造请求签名串
     * @param method
     * @param url
     * @param timestamp
     * @param nonceStr
     * @param body
     * @return
     */
    static String buildMessage(String method, HttpUrl url, long timestamp, String nonceStr, String body) {
        String canonicalUrl = url.encodedPath();
        if (url.encodedQuery() != null) {
            canonicalUrl += "?" + url.encodedQuery();
        }
        return method + "\n"
                + canonicalUrl + "\n"
                + timestamp + "\n"
                + nonceStr + "\n"
                + body + "\n";
    }

    /**
     * 生成签名
     * @param message  签名串
     * @param privateKey 商户私钥
     * @return
     * @throws RemoteException
     * @throws RuntimeException
     */
    static String sign(byte[] message, String privateKey) throws RemoteException,RuntimeException{
        Signature sign = null;
        String stringSign = null;
        try {
            sign = Signature.getInstance("SHA256withRSA");
            try {
                sign.initSign(PemUtil.loadPrivateKeyFromString(privateKey));
                try {
                    sign.update(message);
                    stringSign = Base64.getEncoder().encodeToString(sign.sign());
                } catch (SignatureException e) {
                    throw new RemoteException(e.getMessage());
                }
            } catch (InvalidKeyException e) {
                throw new RemoteException(e.getMessage());
            }
        } catch (NoSuchAlgorithmException e) {
            throw new RemoteException(e.getMessage());
        }
        return stringSign;
    }

 

支付示例：

    /**
     * 支付
     * @param privateKeyPath
     * @param privateKey
     * @return
     * @throws RemoteException
     */
    public static JSONObject pay() throws RemoteException{
        //应用appid
        String appid = "wxd*****3f";    
        //支付商户id
        String merchantId = "163***20";
        //支付密钥
        String apiV3Key = "5dc*******413";
        //商户系列号
        String merchantSerialNumber = "62C345476F*****3E71981";
        //商户商户私钥路径
        String privateKeyPath = this.getClass().getResource("/static/wechat/apiclient_key.pem").getPath();
        //使用hutool获取证书文件内容 privateKey
        FileReader fileReader = new FileReader(privateKeyPath);
        String privateKey = fileReader.readString();

        //微信支付下单API
        String url = "https://api.mch.weixin.qq.com/v3/pay/transactions/jsapi";
        HttpUrl httpurl = HttpUrl.parse(url);
        JSONObject data = new JSONObject();
        JSONObject amount = new JSONObject();
        JSONObject payer = new JSONObject();
        //随机数 这里示例我先用hutool随机生成
        String nonce_str = String.valueOf(RandomUtil.randomInt(1043243, 100432432));
        //订单号 这里示例我先用hutool随机生成
        String out_trade_no = String.valueOf(RandomUtil.randomInt(1043243, 100432432));
        //当前时间戳
        long timestamp = System.currentTimeMillis()/1000;
        data.put("mchid",merchantId);
        data.put("out_trade_no",out_trade_no);
        data.put("appid",appid);
        data.put("description","支付测试");
        data.put("notify_url","https://notify_url");
        amount.put("total",1);
        amount.put("currency","CNY");
        payer.put("openid","oYZ*******HAhG8");
        data.put("amount",amount);
        data.put("payer",payer);
        String message = buildMessage("POST", httpurl, timestamp, nonce_str, data.toJSONString());
        String signature = null;
        try {
            //获取请求签名
            signature = sign(message.getBytes("utf-8"),privateKey);
        } catch (UnsupportedEncodingException e) {
            throw new RemoteException(e.getMessage());
        }
        //生成请求头
        String header = buildHeader(merchantId,nonce_str,signature,timestamp,merchantSerialNumber);
        //发起请求
        String result = HttpRequest.post(url)
                .body(data.toJSONString())
                .header("Content-Type", "application/json")
                .header("Accept", "application/json")
                .header("Authorization",header)
                .execute().body();
        JSONObject resultJson = JSONObject.parseObject(result);
        JSONObject requestData = new JSONObject();
        if(resultJson.get("code") != null){
            requestData.put("code",100);
            requestData.put("msg",resultJson.getString("message"));
        }else{
            String prepay_id = resultJson.getString("prepay_id");
            JSONObject payData = payData(appid,timestamp,nonce_str,prepay_id,privateKey);
            requestData.put("code",200);
            requestData.put("res",payData);
        }
        return requestData;
    }

    /**
     * JSAPI调起支付
     * @param appid
     * @param timestamp
     * @param nonceStr
     * @param prepayId
     * @param privateKey
     * @return
     * @throws RemoteException
     */
    public static JSONObject payData(String appid, long timestamp, String nonceStr, String prepayId,String privateKey) throws RemoteException{
        String payMessage = payMessage(appid,timestamp,nonceStr,prepayId);
        JSONObject data = new JSONObject();
        try {
            String paySign = sign(payMessage.getBytes("utf-8"),privateKey);
            data.put("appId",appid);
            data.put("timeStamp",timestamp);
            data.put("package","prepay_id="+prepayId);
            data.put("signType","RSA");
            data.put("paySign",paySign);
            data.put("nonceStr",nonceStr);

        } catch (UnsupportedEncodingException e) {
            throw new RemoteException(e.getMessage());
        }
        return data;
    }