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微信支付

简介​

微信支付是腾讯旗下的第三方支付平台，为用户提供安全、快捷的支付服务。支持多种支付方式，包括扫码支付、公众号支付、小程序支付、APP支付等。本文档主要介绍JSAPI支付（公众号支付）的接入流程和代码实现。

JSAPI支付是用户在微信中打开商户的H5页面，商户在H5页面通过调用微信支付提供的JSAPI接口调起微信支付模块完成支付。适用于在微信客户端内的网页应用。

参考资料​

支付流程​

关键代码实现​

前端调用（JavaScript）​

// 引入微信JSSDK
// CDN: <script src="https://res.wx.qq.com/open/js/jweixin-1.6.0.js"></script>
// npm: npm install weixin-js-sdk

// wx.config 的签名参数需由后端的 JS-SDK 签名接口下发
wx.config({
  debug: false,
  appId: 'your_app_id',
  timestamp: '',
  nonceStr: '',
  signature: '',
  jsApiList: ['chooseWXPay']
});

// 发起支付请求
async function createWxPayOrder(orderData) {
  const response = await fetch('/api/wxpay/create-order', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(orderData)
  });
  
  const payParams = await response.json();
  
  wx.chooseWXPay({
    timestamp: payParams.timeStamp,
    nonceStr: payParams.nonceStr,
    package: payParams.package,
    signType: 'RSA',
    paySign: payParams.paySign,
    success: () => {
      // 支付成功，跳转结果页或轮询订单状态，最终状态以后端异步通知为准
    },
    fail: () => {
      // 支付失败或取消，提示用户重试
    }
  });
}

后端实现​

// 使用微信官方SDK
import com.wechat.pay.java.core.Config;
import com.wechat.pay.java.core.RSAAutoCertificateConfig;
import com.wechat.pay.java.service.payments.jsapi.JsapiServiceExtension;
import com.wechat.pay.java.service.payments.jsapi.model.*;

public class WxPayService {
  private Config config;
  private JsapiServiceExtension service;
  
  public WxPayService(WxPayConfig wxConfig) {
    this.config = new RSAAutoCertificateConfig.Builder()
      .merchantId(wxConfig.getMchId())
      .privateKeyFromPath(wxConfig.getPrivateKeyPath())
      .merchantSerialNumber(wxConfig.getSerialNo())
      .apiV3Key(wxConfig.getApiV3Key())
      .build();
    this.service = new JsapiServiceExtension.Builder().config(config).build();
  }
  
  // 统一下单：返回值含 timeStamp、nonceStr、packageVal、paySign，供前端 wx.chooseWXPay 使用
  public PrepayWithRequestPaymentResponse createOrder(OrderData orderData) {
    PrepayRequest request = new PrepayRequest();
    request.setAppid(orderData.getAppId());
    request.setMchid(orderData.getMchId());
    request.setDescription(orderData.getDescription());
    request.setOutTradeNo(orderData.getOutTradeNo());
    request.setNotifyUrl(orderData.getNotifyUrl());
    
    Amount amount = new Amount();
    amount.setTotal(orderData.getAmount());
    amount.setCurrency("CNY");
    request.setAmount(amount);
    
    Payer payer = new Payer();
    payer.setOpenid(orderData.getOpenid());
    request.setPayer(payer);
    
    return service.prepayWithRequestPayment(request);
  }
  
  // 查询订单
  public Transaction queryOrder(String outTradeNo) {
    QueryOrderByOutTradeNoRequest request = new QueryOrderByOutTradeNoRequest();
    request.setOutTradeNo(outTradeNo);
    return service.queryOrderByOutTradeNo(request);
  }
}

配置文件​

{
  "wxpay": {
    "appId": "your_app_id",
    "mchId": "your_mch_id",
    "apiV3Key": "your_api_v3_key",
    "serialNo": "your_merchant_cert_serial_no",
    "privateKeyPath": "./cert/apiclient_key.pem",
    "platformCertPath": "./cert/wechatpay_platform_cert.pem",
    "platformCertSerial": "platform_cert_serial_no",
    "notifyUrl": "https://your-domain.com/api/wxpay/notify"
  }
}