java扫码支付，支付码支持支付宝微信银联三合一

您好！您可以使用第三方支付库来实现Java扫码支付，支持支付宝、微信和银联三合一。以下是一个简单的示例代码：

import com.alipay.api.AlipayApiException;
import com.alipay.api.AlipayClient;
import com.alipay.api.DefaultAlipayClient;
import com.alipay.api.request.AlipayTradePrecreateRequest;
import com.alipay.api.response.AlipayTradePrecreateResponse;
import com.github.wxpay.sdk.WXPay;
import com.github.wxpay.sdk.WXPayConfigImpl;
import com.github.wxpay.sdk.WXPayConstants;
import com.github.wxpay.sdk.WXPayUtil;

import java.util.HashMap;
import java.util.Map;

public class QRCodePayment {

    // 支付宝相关配置
    private static final String ALIPAY_APP_ID = "your_alipay_app_id";
    private static final String ALIPAY_PRIVATE_KEY = "your_alipay_private_key";
    private static final String ALIPAY_PUBLIC_KEY = "your_alipay_public_key";
    private static final String ALIPAY_GATEWAY = "https://openapi.alipay.com/gateway.do";

    // 微信支付相关配置
    private static final String WX_PAY_APP_ID = "your_wxpay_app_id";
    private static final String WX_PAY_MCH_ID = "your_wxpay_mch_id";
    private static final String WX_PAY_KEY = "your_wxpay_key";
    private static final String WX_PAY_NOTIFY_URL = "your_wxpay_notify_url";
    private static final String WX_PAY_TRADE_TYPE = "NATIVE";

    public static void main(String[] args) {
        // 生成支付宝付款码
        String alipayQRCode = generateAlipayQRCode("your_order_id", "100.00");
        System.out.println("支付宝付款码：" + alipayQRCode);

        // 生成微信付款码
        String wechatQRCode = generateWechatQRCode("your_order_id", "100");
        System.out.println("微信付款码：" + wechatQRCode);
    }

    public static String generateAlipayQRCode(String orderId, String amount) {
        AlipayClient alipayClient = new DefaultAlipayClient(ALIPAY_GATEWAY, ALIPAY_APP_ID, ALIPAY_PRIVATE_KEY, "json", "UTF-8", ALIPAY_PUBLIC_KEY, "RSA2");
        AlipayTradePrecreateRequest request = new AlipayTradePrecreateRequest();
        request.setBizContent("{\"out_trade_no\":\"" + orderId + "\",\"total_amount\":\"" + amount + "\",\"subject\":\"订单支付\",\"store_id\":\"001\"}");
        try {
            AlipayTradePrecreateResponse response = alipayClient.execute(request);
            if (response.isSuccess()) {
                return response.getQrCode();
            } else {
                System.out.println("生成支付宝付款码失败：" + response.getSubMsg());
            }
        } catch (AlipayApiException e) {
            e.printStackTrace();
        }
        return null;
    }

    public static String generateWechatQRCode(String orderId, String amount) {
        WXPayConfigImpl config = new WXPayConfigImpl();
        config.setAppID(WX_PAY_APP_ID);
        config.setMchID(WX_PAY_MCH_ID);
        config.setKey(WX_PAY_KEY);
        config.setHttpConnectTimeoutMs(5000);
        config.setHttpReadTimeoutMs(10000);

        Map<String, String> data = new HashMap<>();
        data.put("appid", WX_PAY_APP_ID);
        data.put("mch_id", WX_PAY_MCH_ID);
        data.put("nonce_str", WXPayUtil.generateNonceStr());
        data.put("body", "订单支付");
        data.put("out_trade_no", orderId);
        data.put("total_fee", amount);
        data.put("spbill_create_ip", "127.0.0.1");
        data.put("notify_url", WX_PAY_NOTIFY_URL);
        data.put("trade_type", WX_PAY_TRADE_TYPE);

        try {
            WXPay wxPay = new WXPay(config, WXPayConstants.SignType.MD5, false);
            Map<String, String> resultMap = wxPay.unifiedOrder(data);
            if ("SUCCESS".equals(resultMap.get("return_code")) && "SUCCESS".equals(resultMap.get("result_code"))) {
                return resultMap.get("code_url");
            } else {
                System.out.println("生成微信付款码失败：" + resultMap.get("return_msg"));
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
}

请注意，上述代码只是一个简单示例，实际使用中需要替换为您自己的支付宝和微信支付配置参数，并且需要适配具体的支付库和接口。希望对您有帮助！如果还有其他问题，请随时提问。