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微信小程序支付Jsapi下單Java版保姆級(jí)教程

更新時(shí)間：2025年07月01日 10:20:52 作者：小江-

微信支付作為國(guó)內(nèi)領(lǐng)先的第三方支付平臺(tái),為商戶提供了多樣化的支付解決方案,包括JSAPI支付、APP支付、H5支付、Native支付以及小程序支付,這篇文章主要介紹了微信小程序支付Jsapi下單Java版的相關(guān)資料,需要的朋友可以參考下

前置環(huán)境

jdk：21
maven：3.9.9

需要自己去注冊(cè)申請(qǐng)微信小程序和微信支付平臺(tái)商戶號(hào)綁定

注意上述兩張圖片是微信公眾平臺(tái)和微信支付平臺(tái)，兩個(gè)地方的appid和商戶號(hào)必須得對(duì)的上

支付產(chǎn)品許可申請(qǐng)

需要把這個(gè)申請(qǐng)上，這個(gè)就不做贅述了，這個(gè)跟著申請(qǐng)內(nèi)容填資料就行了。

支付參數(shù)申請(qǐng)

這里點(diǎn)擊進(jìn)去后申請(qǐng)一個(gè)證書

然后進(jìn)入這個(gè)API安全，這里比較關(guān)鍵，注意操作步驟。

這里的密鑰記清楚，最好新建一個(gè)文件做一個(gè)備注。

點(diǎn)擊這個(gè)下載，按照這個(gè)下載證書文檔，操作，這里注意的是這個(gè)outputFilePath以及apiclinet_key.pem地址

apiclinet_key.pem地址

這個(gè)地址需要在解密回調(diào)里面去申請(qǐng)，同樣里面的密鑰也需要記住。

然后按照這個(gè)工具里面的操作進(jìn)行來回復(fù)制就會(huì)得到一個(gè)文件，這個(gè)文件里面的apiclinet_key.pem存放的地址。

這樣操作下來我們就得到一個(gè)

java -jar CertificateDownloader.jar -k CZBK5123643FFDuv3 -m 1622408443 -f E:\code\AI\乞討\1622408443_20250305_cert\apiclient_key.pem -s 495F550990E8FF3FC72C7 -o E:\www\code

運(yùn)行后

得到密鑰文件。至此我們所需要的文件已全部收集齊全。

代碼：

application.yaml

cant:
  wechat:
    # 微信公眾平臺(tái)里面的小程序appid
    appid: wx8b8656de482b
    # 商戶號(hào)
    mchid: 1622408443
    # 商戶API證書里面的序列號(hào)
    mchSerialNo: 405172E0770000864CE6A4136411
    # 解密回調(diào)的密鑰
    apiV3Key: Cwxpay435434323FFDuv3
    # 這個(gè)是解密回調(diào)也就是生成的（微信支付商戶平臺(tái)證書工具）
    privateKeyFilePath: E:\code\AI\乞討\1622408443_20250307_cert\apiclient_cert.pem
    # 這個(gè)是通cmd生成的
    weChatPayCertFilePath: E:\www\code\wechatpay_54D388B975FD231C6CA45BE67F78D0E4181AC0C2.pem
    # 支付成功回調(diào)地址
    notifyUrl: https://taluop.top/cant/notify

導(dǎo)入依賴

<dependency>
            <groupId>com.github.wechatpay-apiv3</groupId>
            <artifactId>wechatpay-java</artifactId>
            <version>0.2.10</version>
        </dependency>

配置類

@Component
@ConfigurationProperties(prefix = "cant.wechat")
@Data
@EnableConfigurationProperties
public class WeChatProperties {
    private String appid; //小程序的appid
    private String secret; //小程序的秘鑰
    private String mchid; //商戶號(hào)
    private String mchSerialNo; //商戶API證書的證書序列號(hào)
    private String privateKeyFilePath; //商戶私鑰文件
    private String apiV3Key; //證書解密的密鑰
    private String weChatPayCertFilePath; //平臺(tái)證書
    private String notifyUrl; //支付成功的回調(diào)地址
    private String refundNotifyUrl; //退款成功的回調(diào)地址

}

工具類

/**
 * 微信支付工具類
 */
@Component
public class WeChatPayUtil {

    //微信支付下單接口地址
    public static final String JSAPI = "https://api.mch.weixin.qq.com/v3/pay/transactions/jsapi";

    //申請(qǐng)退款接口地址
    public static final String REFUNDS = "https://api.mch.weixin.qq.com/v3/refund/domestic/refunds";

    @Autowired
    private WeChatProperties weChatProperties;

    /**
     * 獲取調(diào)用微信接口的客戶端工具對(duì)象
     *
     * @return
     */
    private CloseableHttpClient getClient() {
        PrivateKey merchantPrivateKey = null;
        try {
            // merchantPrivateKey商戶API私鑰，如何加載商戶API私鑰請(qǐng)看常見問題
            merchantPrivateKey = PemUtil.loadPrivateKey(new FileInputStream(new File(weChatProperties.getPrivateKeyFilePath())));
            // 加載平臺(tái)證書文件
            X509Certificate x509Certificate = PemUtil.loadCertificate(new FileInputStream(new File(weChatProperties.getWeChatPayCertFilePath())));
            // wechatPayCertificates微信支付平臺(tái)證書列表。你也可以使用“定時(shí)更新平臺(tái)證書功能”
            List<X509Certificate> wechatPayCertificates = Arrays.asList(x509Certificate);

            WechatPayHttpClientBuilder builder = WechatPayHttpClientBuilder.create()
                    .withMerchant(weChatProperties.getMchid(), weChatProperties.getMchSerialNo(), merchantPrivateKey)
                    .withWechatPay(wechatPayCertificates);

            // 通過WechatPayHttpClientBuilder構(gòu)造的HttpClient，會(huì)自動(dòng)的處理簽名和驗(yàn)簽
            CloseableHttpClient httpClient = builder.build();
            return httpClient;
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 發(fā)送post方式請(qǐng)求
     *
     * @param url
     * @param body
     * @return
     */
    private String post(String url, String body) throws Exception {
        CloseableHttpClient httpClient = getClient();

        HttpPost httpPost = new HttpPost(url);
        httpPost.addHeader(HttpHeaders.ACCEPT, ContentType.APPLICATION_JSON.toString());
        httpPost.addHeader(HttpHeaders.CONTENT_TYPE, ContentType.APPLICATION_JSON.toString());
        httpPost.addHeader("Wechatpay-Serial", weChatProperties.getMchSerialNo());
        httpPost.setEntity(new StringEntity(body, "UTF-8"));

        CloseableHttpResponse response = httpClient.execute(httpPost);
        try {
            String bodyAsString = EntityUtils.toString(response.getEntity());
            return bodyAsString;
        } finally {
            httpClient.close();
            response.close();
        }
    }

    /**
     * jsapi下單
     *
     * @param orderNum    商戶訂單號(hào)
     * @param total       總金額
     * @param description 商品描述
     * @param openid      微信用戶的openid
     * @return
     */
    private String jsapi(String orderNum, BigDecimal total, String description, String openid) throws Exception {
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("appid", weChatProperties.getAppid());
        jsonObject.put("mchid", weChatProperties.getMchid());
        jsonObject.put("description", description);
        jsonObject.put("out_trade_no", orderNum);
        jsonObject.put("notify_url", weChatProperties.getNotifyUrl());

        JSONObject amount = new JSONObject();
        amount.put("total", total.multiply(new BigDecimal(100)).setScale(2, BigDecimal.ROUND_HALF_UP).intValue());
        amount.put("currency", "CNY");

        jsonObject.put("amount", amount);

        JSONObject payer = new JSONObject();
        payer.put("openid", openid);

        jsonObject.put("payer", payer);

        String body = jsonObject.toJSONString();
        return post(JSAPI, body);
    }

    /**
     * 小程序支付
     *
     * @param orderNum    商戶訂單號(hào)
     * @param total       金額，單位 元
     * @param description 商品描述
     * @param openid      微信用戶的openid
     * @return
     */
    public JSONObject pay(String orderNum, BigDecimal total, String description, String openid) throws Exception {
        //統(tǒng)一下單，生成預(yù)支付交易單
        String bodyAsString = jsapi(orderNum, total, description, openid);
        //解析返回結(jié)果
        JSONObject jsonObject = JSON.parseObject(bodyAsString);

        System.out.println(jsonObject);

        String prepayId = jsonObject.getString("prepay_id");
        if (prepayId != null) {
            String timeStamp = String.valueOf(System.currentTimeMillis() / 1000);
            String nonceStr = RandomStringUtils.randomNumeric(32);
            ArrayList<Object> list = new ArrayList<>();
            list.add(weChatProperties.getAppid());
            list.add(timeStamp);
            list.add(nonceStr);
            list.add("prepay_id=" + prepayId);
            //二次簽名，調(diào)起支付需要重新簽名
            StringBuilder stringBuilder = new StringBuilder();
            for (Object o : list) {
                stringBuilder.append(o).append("\n");
            }
            String signMessage = stringBuilder.toString();
            byte[] message = signMessage.getBytes();

            Signature signature = Signature.getInstance("SHA256WithRSA");
            signature.initSign(PemUtil.loadPrivateKey(new FileInputStream(new File(weChatProperties.getPrivateKeyFilePath()))));
            signature.update(message);
            String packageSign = Base64.getEncoder().encodeToString(signature.sign());

            //構(gòu)造數(shù)據(jù)給微信小程序，用于調(diào)起微信支付
            JSONObject jo = new JSONObject();
            jo.put("timeStamp", timeStamp);
            jo.put("nonceStr", nonceStr);
            jo.put("package", "prepay_id=" + prepayId);
            jo.put("signType", "RSA");
            jo.put("paySign", packageSign);

            return jo;
        }
        return jsonObject;
    }
    /**
     * 發(fā)送get方式請(qǐng)求
     *
     * @param url
     * @return
     */
    private String get(String url) throws Exception {
        CloseableHttpClient httpClient = getClient();

        HttpGet httpGet = new HttpGet(url);
        httpGet.addHeader(HttpHeaders.ACCEPT, ContentType.APPLICATION_JSON.toString());
        httpGet.addHeader(HttpHeaders.CONTENT_TYPE, ContentType.APPLICATION_JSON.toString());
        httpGet.addHeader("Wechatpay-Serial", weChatProperties.getMchSerialNo());

        CloseableHttpResponse response = httpClient.execute(httpGet);
        try {
            String bodyAsString = EntityUtils.toString(response.getEntity());
            return bodyAsString;
        } finally {
            httpClient.close();
            response.close();
        }
    }


    /**
     * 申請(qǐng)退款
     *
     * @param outTradeNo    商戶訂單號(hào)
     * @param outRefundNo   商戶退款單號(hào)
     * @param refund        退款金額
     * @param total         原訂單金額
     * @return
     */
    public String refund(String outTradeNo, String outRefundNo, BigDecimal refund, BigDecimal total) throws Exception {
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("out_trade_no", outTradeNo);
        jsonObject.put("out_refund_no", outRefundNo);

        JSONObject amount = new JSONObject();
        amount.put("refund", refund.multiply(new BigDecimal(100)).setScale(2, BigDecimal.ROUND_HALF_UP).intValue());
        amount.put("total", total.multiply(new BigDecimal(100)).setScale(2, BigDecimal.ROUND_HALF_UP).intValue());
        amount.put("currency", "CNY");

        jsonObject.put("amount", amount);
        jsonObject.put("notify_url", weChatProperties.getRefundNotifyUrl());

        String body = jsonObject.toJSONString();

        //調(diào)用申請(qǐng)退款接口
        return post(REFUNDS, body);
    }
}

遇到的問題：

應(yīng)答的狀態(tài)碼不為200-299，商戶證書序列號(hào)有誤。

你需要找到最近操作的證書序列號(hào)
找不到證書序列號(hào)對(duì)應(yīng)的證書

這個(gè)地址對(duì)應(yīng)的看一下是否是最新的
Java HotSpot(TM) 64-Bit Server VM warning: Sharing is only supported for boot loader classes because bootstrap classpath has been appendedranh

這個(gè)需要的是apiclient_key.pem文件，這個(gè)是由apiclient_cert.pem文件加序列號(hào)生成的文件。