[Java]zxing生成qrcode二维码，带水印图片，中间带一个logo

在之前一篇文章，详细介绍了利用Zxing生成QRCode二维码以及BarCode条形码，并可以输出到文件或者输出到网页，很多时候，我们生成的二维码中间需要加一个logo图片，本次我们演示如何做：

一些依赖等基础准备工作，就不介绍了，如有需求，可以看：https://blog.terrynow.com/2021/02/06/java-google-zxing-generate-qrcode-or-barcode-output-to-file-or-web/

public static void main(String[] args) throws Exception {
    int qrWithAndHeight = 800; // 生成QRCode的图片长宽，假设时正方形
    int logoWithAndHeight = 80; // 嵌入的Logo的图片长宽，实际的logo图片可以比这个大，比这个小就不清晰

    String qrContent = "https://blog.terrynow.com"; // 实际QR扫出来的内容
    BufferedImage qrCodeImage = generateQRCode(qrContent, qrWithAndHeight);

    // 准备画图
    Graphics2D g = qrCodeImage.createGraphics();
    g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
 
    // 读取logo文件，计算正中央的位置，画到qrCode图片中去
    Image logoImage = ImageIO.read(new File("/Users/Terry/Pictures/logo.jpg"));
    int logoXOrY = (qrWithAndHeight - logoWithAndHeight) / 2;
    g.drawImage(logoImage, logoXOrY, logoXOrY, logoWithAndHeight, logoWithAndHeight, null);

    g.dispose();

    //保存到文件，如需输出到网页，请看 https://blog.terrynow.com/2021/02/06/java-google-zxing-generate-qrcode-or-barcode-output-to-file-or-web/
    ImageIO.write(qrCodeImage, "jpeg", new File("/Users/Terry/Downloads/qrcode.jpg"));

}

public static BufferedImage generateQRCode(String content, int widthAndHeight) throws Exception {
    Hashtable<EncodeHintType, Object> hints = new Hashtable<>();
    hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
    hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
    hints.put(EncodeHintType.MARGIN, 2);
    BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, widthAndHeight, widthAndHeight, hints);
    return toBufferedImage(bitMatrix);
}

private static BufferedImage toBufferedImage(BitMatrix matrix) {
    int black = 0xFF000000;//用于设置图案的颜色
    int white = 0xFFFFFFFF; //用于背景色
    int width = matrix.getWidth();
    int height = matrix.getHeight();
    BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    for (int x = 0; x < width; x++) {
        for (int y = 0; y < height; y++) {
            image.setRGB(x, y, (matrix.get(x, y) ? black : white));
//              image.setRGB(x, y,  (matrix.get(x, y) ? Color.YELLOW.getRGB() : Color.CYAN.getRGB()));
        }
    }
    return image;
}

如图，一个带logo的二维码就做好啦