Java 支付寶當面付生成二維碼支付實現

參考官方APIalipay.trade.precreate(統一收單線下交易預創建)

1. maven依賴：

        <!-- 支付寶支付sdk -->
        <dependency>
            <groupId>com.alipay.sdk</groupId>
            <artifactId>alipay-sdk-java</artifactId>
            <version>4.9.124.ALL</version>
        </dependency>

        <!-- 二維碼工具 -->
        <dependency>
            <groupId>com.google.zxing</groupId>
            <artifactId>core</artifactId>
            <version>3.3.3</version>
        </dependency>
        <dependency>
            <groupId>com.google.zxing</groupId>
            <artifactId>javase</artifactId>
            <version>3.3.3</version>
        </dependency>

2. 準備工作：

AlipayConfig 配置類在第一篇關於支付寶支付文章裏有寫到：
Java 支付寶手機網站支付下單 支付回調 及訂單查詢實現
這裏直接用了
file.qrCode是在配置文件裏寫到的二維碼圖片本地存儲位置，

需要在項目裏配置虛擬路徑，參考SpringBoot文件虛擬路徑配置，
以及圖片開放訪問，有權限限制的項目需要這一步，項目不同開放的方式也不同，舉例：

如果是分佈式項目的話，集成MinIO來存儲圖片會更好，參考
Java MinIO文件上傳返回訪問路徑及訪問配置

3. 代碼：

QrCodeUtil

import com.google.zxing.*;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.Hashtable;

public class QrCodeUtil {
    /**
     * 生成包含字符串信息的二維碼圖片
     * @param outputStream 文件輸出流路徑
     * @param content 二維碼攜帶信息
     */
    public static boolean createQrCode(OutputStream outputStream, String content) throws WriterException, IOException{
        //設置二維碼糾錯級別ＭＡＰ
        Hashtable<EncodeHintType, ErrorCorrectionLevel> hintMap = new Hashtable<EncodeHintType, ErrorCorrectionLevel>();
        hintMap.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);  // 矯錯級別
        QRCodeWriter qrCodeWriter = new QRCodeWriter();
        //創建比特矩陣(位矩陣)的QR碼編碼的字符串
        BitMatrix byteMatrix = qrCodeWriter.encode(content, BarcodeFormat.QR_CODE, 900, 900, hintMap);
        // 使BufferedImage勾畫QRCode  (matrixWidth 是行二維碼像素點)
        int matrixWidth = byteMatrix.getWidth();
        BufferedImage image = new BufferedImage(matrixWidth-200, matrixWidth-200, BufferedImage.TYPE_INT_RGB);
        image.createGraphics();
        Graphics2D graphics = (Graphics2D) image.getGraphics();
        graphics.setColor(Color.WHITE);
        graphics.fillRect(0, 0, matrixWidth, matrixWidth);
        // 使用比特矩陣畫並保存圖像
        graphics.setColor(Color.BLACK);
        for (int i = 0; i < matrixWidth; i++){
            for (int j = 0; j < matrixWidth; j++){
                if (byteMatrix.get(i, j)){
                    graphics.fillRect(i-100, j-100, 1, 1);
                }
            }
        }
        return ImageIO.write(image, "JPEG", outputStream);
    }
}

controller

    @Value("${file.qrCode}")
    private String qrCode;

    @PreAuthorize("@el.check('anonymous')")	// 匿名訪問
    @PostMapping("/alipayPrecreate")
    public ResponseEntity alipayPrecreate(@RequestBody Map params) throws Exception {
		// 創建訂單並返回訂單id
        ShopOrderDTO shopOrderDTO = createOrder(params);

		// 支付請求參數準備 
        AlipayConfig alipayConfig = new AlipayConfig(shopDeviceService);

        AlipayClient alipayClient = new DefaultAlipayClient(alipayConfig.getUrl(), alipayConfig.getAppId(),
                alipayConfig.getRSAPrivateKey(), alipayConfig.getFormat(), alipayConfig.getCharset(),
                alipayConfig.getAliPayPublicKey(), alipayConfig.getSignType());
        AlipayTradePrecreateRequest req = new AlipayTradePrecreateRequest();

        AlipayTradePrecreateModel model=new AlipayTradePrecreateModel();
        model.setOutTradeNo(shopOrderDTO.getId().toString());
        model.setSubject(alipayConfig.getSubject());
        String amount = String.valueOf(shopOrderDTO.getAmount().floatValue() / 100);
        model.setTotalAmount(amount);
        req.setBizModel(model);
        req.setNotifyUrl(alipayConfig.getNotifyUrl());

        logger.info("發起AliPay下單請求");
        AlipayTradePrecreateResponse execute = alipayClient.execute(req);

        String result = execute.getBody();
        JSONObject res = JSON.parseObject(result);
        Map response = (Map) res.get("alipay_trade_precreate_response");
        if (response.get("code").toString().equals("10000") && response.get("qr_code") != null) {
        
        	// 將返回的二維碼存儲至本地
            String path = qrCode + shopOrderDTO.getId() + "AliPay.jpg";
            String httpPath = "/qrCode/" + shopOrderDTO.getId() + "AliPay.jpg";
            File file = new File(path);
            if (!file.getParentFile().exists()) {
                file.getParentFile().mkdirs();
            }
            QrCodeUtil.createQrCode(new FileOutputStream(file), response.get("qr_code").toString());
            
            // 將圖片可訪問的url返回給前端
            response.put("qrcode", httpPath);
            
            return new ResponseEntity<>(response, HttpStatus.OK);
        }
        return new ResponseEntity<>(response, HttpStatus.OK);

    }