​前提

在微信商户平台成为商家，按照官网的文档进行配置，弄好下载证书，将证书复制到后端的项目上

​

实现过程

GitHub - yangfuhe/node-wxpay: 微信支付APIv3 for nodejs

安装 wxpay-v3

npm i wxpay-v3 --save

# 如已安装旧版, 重新安装最新版
npm i wxpay-v3@latest

或者使用 wechatpay-node-v3

创建 WxPayUtils.js

const RSA = require('./wx_rsa');
class WxPayUtils {
    constructor(privateKey,appId) {
        this.privateKey =privateKey;
        this.appId = appId;
    }
    signLong  (data) {
        // let privateKey =private_key
        let sign_rsa = new RSA.RSAKey();
        sign_rsa = RSA.KEYUTIL.getKey(this.privateKey);
        let hashAlg = 'sha256';//sha256//此处换成腾讯要求的方式
        let Sig = sign_rsa.signString(data, hashAlg);
        Sig = RSA.hex2b64(Sig); // hex 转 b64
        return Sig;
    }

    paysign(options){//发起支付签的字段准备
        let timeStamp=this.createTimeStamp(),//时间戳
            nonceStr=this.randomString(),//32位随机数
            Ppackage= `prepay_id=${options}`,//prepay_id
            signType= 'RSA';//加签方式
        //appId、timeStamp、nonceStr、package
        let PpaySign=`${this.appId}\n${timeStamp}\n${nonceStr}\n${Ppackage}\n`;//需要加签的字段拼接
        let cryptStr=this.signLong(PpaySign);//生成签名
        let paySign=cryptStr;
        return {timeStamp,nonceStr,Ppackage,signType,paySign};
    }

    createTimeStamp(){
        return parseInt(new Date().getTime() / 1000) + ''
    }

    randomString(){
        const chars='ABCDEFGHJKMNPQRSTWXYZabcdefhijkmnprstwxyz2345678'; //默认去掉了容易混淆的字符oOLl,9gq,Vv,Uu,I1
        const len=32;
        const maxPos=chars.length;
        let pwd='';
        for(let i=0;i

 创建wx_rsa.js

GitHub - UFO0001/WX_RSA 到github上下载 在utils包

或者去这里复制 

file/wx_rsa.js · huyande/blogimage - Gitee.com

const Payment = require('wxpay-v3');
const path = require("path");
const Ret = require('../common/ret');
const WxPayUtils = require('../common/WxPayUtils');
const private_key = require('fs').readFileSync(path.resolve(__dirname, '../wxpay_20220512_cert/apiclient_key.pem')).toString()
const appid = '微信小程序的appid';
const paymnet = new Payment({
    appid: appid,
    mchid: '商户号',
    private_key: private_key,//或者直接复制证书文件内容
    serial_no:'证书编号，在商户后台申请证书后会有编号',
    apiv3_private_key:'api v3 接口设置的秘钥',
    notify_url: '支付回调地址',
});

const wxPay = new WxPayUtils(private_key,appid);

/**
 * amount 单位是分
 * @param req
 * @param res
 * @param next
 * @returns {Promise<*>}
 */
exports.createWxPay = async function (req,res,next){
    let openid = req.query.openid;
    let amount = req.query.amount;
    let current_user = req.session.wxuser;
    let result = await paymnet.jsapi({
        description:'打赏支付',
        out_trade_no:Date.now().toString(),
        amount:{
            total:amount
        },
        payer:{
            openid:openid
        },
    }).catch(e=>{
        return new Ret({ code: -1,data:e}).send(res);
    });
    let prepay_id = JSON.parse(result.data).prepay_id;
    let sign = wxPay.paysign(prepay_id);
    return new Ret({ code: 0,data:sign}).send(res);
};


/**
 * 支付回调方法
 * @param req
 * @param res
 * @param next
 * @returns {*}
 */
exports.callWxPay = function (req,res,next){
    return new Ret({ code: 0}).send(res);
};

小程序端

testPay(){
		wxpay({openid:'xxx',amount:1}).then(res=>{
			let options = res.data
			wx.requestPayment
			(
				{
					package:options.Ppackage,...options,
					"success":function(res){
						console.log(res)
					},
					"fail":function(res){
						console.log(res)
					}
				}
			)
		})

	}

即可实现​