在Spring Boot项目中接入支付宝扫码支付功能，可以通过以下步骤实现。以下是基于最新搜索结果的详细教程：

alipay:
  easy:
    protocol: https
    gatewayHost: openapi.alipay.com
    signType: RSA2
    appId: your-app-id
    merchantPrivateKey: your-private-key
    alipayPublicKey: alipay-public-key
    notifyUrl: http://your-domain/notify

<dependency>
    <groupId>com.alipay.sdk</groupId>
    <artifactId>alipay-sdk-java</artifactId>
    <version>4.9.79.ALL</version>
</dependency>
<dependency>
    <groupId>cn.hutool</groupId>
    <artifactId>hutool-all</artifactId>
    <version>5.7.22</version>
</dependency>

import com.alipay.api.AlipayClient;
import com.alipay.api.DefaultAlipayClient;
import com.alipay.api.request.AlipayTradePrecreateRequest;
import com.alipay.api.response.AlipayTradePrecreateResponse;
import cn.hutool.qr.QrCodeUtil;

@Service
public class AlipayService {
    @Autowired
    private Environment env;

    public String createQrCode(String subject, String totalAmount) throws Exception {
        AlipayClient alipayClient = new DefaultAlipayClient(
                env.getProperty("alipay.easy.protocol"),
                env.getProperty("alipay.easy.appId"),
                env.getProperty("alipay.easy.merchantPrivateKey"),
                "json",
                "UTF-8",
                env.getProperty("alipay.easy.alipayPublicKey"),
                "RSA2");

        AlipayTradePrecreateRequest request = new AlipayTradePrecreateRequest();
        request.setBizContent("{"
                + "\"out_trade_no\":\"" + UUID.randomUUID().toString().replace("-", "") + "\","
                + "\"total_amount\":\"" + totalAmount + "\","
                + "\"subject\":\"" + subject + "\","
                + "\"product_code\":\"FACE_TO_FACE_PAYMENT\""
                + "}");

        AlipayTradePrecreateResponse response = alipayClient.execute(request);
        if (response.isSuccess()) {
            String qrCodeUrl = response.getQrCode();
            return qrCodeUrl; // 返回二维码链接
        } else {
            throw new RuntimeException("支付二维码生成失败：" + response.getMsg());
        }
    }
}

@RestController
public class PayController {
    @Autowired
    private AlipayService alipayService;

    @GetMapping("/pay")
    public void pay(HttpServletResponse response) throws Exception {
        String qrCodeUrl = alipayService.createQrCode("测试商品", "0.01");
        QrCodeUtil.generate(qrCodeUrl, 300, 300, "png", response.getOutputStream());
    }
}

@PostMapping("/notify")
public String handleNotify(HttpServletRequest request) {
    Map<String, String> params = request.getParameterMap().entrySet().stream()
            .collect(Collectors.toMap(Map.Entry::getKey, e -> e.getValue()[0]));

    boolean verifyResult = AlipaySignature.rsaCheckV1(params, env.getProperty("alipay.easy.alipayPublicKey"), "UTF-8", "RSA2");
    if (verifyResult) {
        String outTradeNo = params.get("out_trade_no");
        String totalAmount = params.get("total_amount");
        // 更新订单状态等业务逻辑
        return "success";
    } else {
        return "fail";
    }
}