利用支付宝当面付实现手机网站支付的步骤

<dependency>
    <groupId>com.alipay.sdk</groupId>
    <artifactId>alipay-sdk-java</artifactId>
    <version>YOUR_SDK_VERSION</version>
</dependency>

import com.alipay.api.*;
import com.alipay.api.request.AlipayTradeWapPayRequest;

public class AlipayService {
    private static final String APP_ID = "your_app_id";
    private static final String APP_PRIVATE_KEY = "your_private_key";
    private static final String ALIPAY_PUBLIC_KEY = "alipay_public_key";

    public String createOrder() {
        AlipayClient alipayClient = new DefaultAlipayClient(
            "https://openapi.alipay.com/gateway.do",
            APP_ID,
            APP_PRIVATE_KEY,
            "json",
            "UTF-8",
            ALIPAY_PUBLIC_KEY,
            "RSA2"
        );

        AlipayTradeWapPayRequest request = new AlipayTradeWapPayRequest();
        request.setReturnUrl("http://your_return_url");
        request.setNotifyUrl("http://your_notify_url");

        request.setBizContent("{" +
            ""out_trade_no":"202401230001", " +
            ""total_amount":"0.01", " +
            ""subject":"测试商品", " +
            ""product_code":"QUICK_WAP_PAY" " +
            "}");

        try {
            String form = alipayClient.pageExecute(request).getBody();
            return form; // 返回支付表单
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
}

import com.alipay.api.internal.util.AlipaySignature;

public void notifyAlipay(HttpServletRequest request) {
    try {
        Map<String, String> params = request.getParameterMap().entrySet().stream()
            .collect(Collectors.toMap(Map.Entry::getKey, e -> String.join(",", e.getValue())));

        boolean signVerified = AlipaySignature.rsaCheckV1(params, ALIPAY_PUBLIC_KEY, "UTF-8", "RSA2");
        if (signVerified) {
            String tradeStatus = params.get("trade_status");
            if ("TRADE_SUCCESS".equals(tradeStatus)) {
                System.out.println("支付成功！");
            } else {
                System.out.println("支付失败！");
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}