Spring Boot QR코드 생성

Source

Dependency

implementation group: 'com.google.zxing', name: 'javase', version: '3.5.0'
implementation group: 'com.google.zxing', name: 'core', version: '3.5.0'

util

public static String makeIdentifyCode(String uuid) throws NoSuchAlgorithmException {
    String hashType = "SHA-256";java.security.MessageDigest md;
    md = java.security.MessageDigest.getInstance(hashType);
    byte[] hashData = md.digest((uuid+new Timestamp(System.currentTimeMillis())).getBytes(StandardCharsets.UTF_8));
    StringBuilder result = new StringBuilder();
    for ( byte b : hashData )
        result.append(Integer.toString((b & 0xff) + 0x100, 16).substring(1));
    return result.toString();
}

public static byte[] makeQrImage(String hash, String name) throws WriterException {
    int width = 200;
    int height = 200;

    Map<EncodeHintType, Object> hints = new EnumMap<>(EncodeHintType.class);
    hints.put(EncodeHintType.MARGIN, 1);
    BitMatrix encode = new MultiFormatWriter().encode(hash, BarcodeFormat.QR_CODE, width, height, hints);
	// emptyQR(encode, 50, 50); // QR코드 로고 넣을시 가운데 비우는 코드
    try {
        BufferedImage qrImage = MatrixToImageWriter.toBufferedImage(encode);

        int combinedHeight = height + 12;
        BufferedImage combined = new BufferedImage(width, combinedHeight, BufferedImage.TYPE_INT_RGB);
        Graphics g = combined.getGraphics();

        g.setColor(Color.WHITE);
        g.fillRect(0, 0, width, combinedHeight);

        g.drawImage(qrImage, 0, 0, null);
        g.setColor(Color.BLACK);
        g.setFont(new Font("Arial", Font.PLAIN, 18));
        FontMetrics fontMetrics = g.getFontMetrics();
        int textWidth = fontMetrics.stringWidth(name);
        int textX = (width - textWidth) / 2;
        int textY = height + (g.getFont().getSize() - 15);

        g.drawString(name, textX, textY);

        g.dispose();

        ByteArrayOutputStream out = new ByteArrayOutputStream();
        ImageIO.write(combined, "PNG", out);

        return out.toByteArray();
    }catch (Exception e){e.fillInStackTrace();}
    return null;
} 

private static BitMatrix emptyQR(BitMatrix bitMatrix, int regionHeight, int regionWidth) {
    int width=bitMatrix.getWidth();
    int height=bitMatrix.getHeight();

    int left=(width-regionWidth)/2;
    int top=(height-regionHeight)/2;

    bitMatrix.setRegion(left,top,regionWidth,regionHeight);
    for (int y = top; y <= top+regionHeight; y++) {
        for (int x = left; x <= left+regionWidth; x++) {
            if(bitMatrix.get(x, y)){
                bitMatrix.unset(x,y);
            };
        }
    }
    return bitMatrix;
}

controller

@GetMapping("/downloadUserQr/{uid}")
public ResponseEntity<byte[]> downloadUserQr(@PathVariable String uid, HttpServletResponse res ) throws Exception {
    byte[] qrImage = null;
    
    Map<String, Object> param = new HashMap<>();
    param.put("uuid", uid);

    if(param.get("uuid") == null) {
        return ResponseEntity.badRequest().build();
    }

    try {
        String uuid = param.get("uuid").toString();
        Map<String, Object> data = fileDao.selectQrHashFromId(uuid);

        if(data == null) {
            return ResponseEntity.badRequest().build();
        } else if(data.get("hash") == null) {
            String genQrHash = StringUtils.makeIdentifyCode(uuid);
            param.put("hash", genQrHash);
            fileDao.updateUserQrHash(param);
            data.put("hash", genQrHash);
        }
        qrImage = StringUtils.makeQrImage(data.get("hash").toString(), data.get("name").toString());

    } catch (Exception e) {
        throw new RuntimeException(e);
    }

    return ResponseEntity.ok().contentType(MediaType.IMAGE_PNG).body(qrImage);
}