微信和支付宝请求退款

    /**
 * 微信退款
 * 
 * @param orderNo
 * @param amount
 */
public static Ret wechatRefund(String orderNo, BigDecimal amount) {
    Prop prop = PropKit.use("wechat.txt");
    // 封装请求参数
    Map<String, String> data = new HashMap<>();
    data.put("appid", prop.get("appid"));
    data.put("mch_id", prop.get("mchid"));
    data.put("nonce_str", StrKit.getRandomUUID());
    data.put("out_trade_no", orderNo);
    data.put("out_refund_no", orderNo);
    String totalFee = String.valueOf(amount.multiply(new BigDecimal("100")).intValue());
    data.put("total_fee", totalFee);
    data.put("refund_fee", totalFee);
    data.put("sign", StringKit.genMd5Sign(data, prop.get("key")));
    // 发送退款请求
    String result = null;
    try {
        // 实例化密码库并设置证书格式
        KeyStore keyStore = KeyStore.getInstance("PKCS12");
        // 将证书文件转为文件输入流
        FileInputStream inputStream = new FileInputStream(new File(prop.get("cert_path")));
        // 加载证书文件流和密码（默认为商户id）到密钥库
        keyStore.load(inputStream, prop.get("mchid").toCharArray());
        SSLContext sslcontext = SSLContexts.custom().loadKeyMaterial(keyStore, prop.get("mchid").toCharArray())
                .build();
        SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslcontext);
        // 构建ssl套接字的证书内容和密码
        CloseableHttpClient httpClient = HttpClients.custom().setSSLSocketFactory(sslsf).build();
        // 创建post请求
        HttpPost httpPost = new HttpPost(prop.get("refund_url"));
        // 填充数据实体
        httpPost.setEntity(new StringEntity(StringKit.mapToXml(data), Const.CHARSET));
        // 发送退款请求
        HttpResponse response = httpClient.execute(httpPost);
        HttpEntity entity = response.getEntity();
        result = EntityUtils.toString(entity, Const.CHARSET);
    } catch (Exception e) {
        e.printStackTrace();
        return Ret.fail("msg", ErrorMsg.REQUEST_FAIL);
    }
    if (StrKit.isBlank(result))
        return Ret.fail("msg", ErrorMsg.REQUEST_FAIL);
    Map<String, String> response = StringKit.xmlToMap(result);
    // 请求成功需返回状态和返回结果均为成功
    if (response == null || !response.get("return_code").equals(UserPaymentRecord.WechatResult.CODE)
            || !response.get("result_code").equals(UserPaymentRecord.WechatResult.CODE)) {
        LogKit.error("请求微信退款失败：" + response.get("return_msg"));
        return Ret.fail("msg", ErrorMsg.REQUEST_FAIL);
    }
    return Ret.ok();
}
/**
 * 支付宝退款
 * 
 * @param orderNo
 * @param amount
 */
public static Ret alipayRefund(String orderNo, BigDecimal amount) {
    Prop prop = PropKit.use("alipay.txt");
    // 获取请求参数
    String serverUrl = prop.get("open_api_domain");
    String appid = prop.get("appid");
    String privateKey = prop.get("private_key");
    String format = "JSON";
    String charset = "UTF-8";
    String alipayPublicKey = prop.get("alipay_public_key");
    String signType = prop.get("sign_type");
    // 实例化支付宝客户端
    AlipayClient alipayClient = new DefaultAlipayClient(serverUrl, appid, privateKey, format, charset,
            alipayPublicKey, signType);
    AlipayTradeRefundRequest request = new AlipayTradeRefundRequest();
    // 填充业务内容
    Map<String, String> bizContent = new HashMap<>();
    bizContent.put("out_trade_no", orderNo);
    bizContent.put("refund_amount", amount.toString());
    request.setBizContent(JsonKit.toJson(bizContent));
    try {
        // 发送退款请求
        if (alipayClient.execute(request).isSuccess())
            return Ret.ok();
    } catch (AlipayApiException e) {
        e.printStackTrace();
        return Ret.fail("msg", ErrorMsg.REQUEST_FAIL);
    }
    return Ret.fail("msg", ErrorMsg.OPERATION_FAIL);
}

注意：微信退款需要登录微信后台下载双向证书

原文地址：https://www.jfinal.com/share/1373