原先工具类只能生成一个普通的二维码
这一期说是要二维码下面要加一个文字
晚上找了一下都比较乱
还是自己稍微改了一下好一点。。

public static MultipartFile createQrCode(String content) {
        Map<EncodeHintType, Object> hints = new HashMap<>();
        hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
        try {
            // 生成矩阵
            BitMatrix bitMatrix = new MultiFormatWriter().encode(content,
                    BarcodeFormat.QR_CODE, IMG_WIDTH, IMG_HEIGHT, hints);
            BufferedImage bufferedImage = MatrixToImageWriter.toBufferedImage(bitMatrix);

            //创建一个ByteArrayOutputStream
            ByteArrayOutputStream os = new ByteArrayOutputStream();
            //把BufferedImage写入ByteArrayOutputStream
            ImageIO.write(bufferedImage, "jpg", os);
            //ByteArrayOutputStream转成InputStream
            InputStream input = new ByteArrayInputStream(os.toByteArray());
            //InputStream转成MultipartFile
            return new MockMultipartFile("file", "qrcode.jpg", "text/plain", input);
        } catch (IOException | WriterException exception) {
            throw new ApplicationException(exception.getMessage());
        }
    }

    public static MultipartFile createQrCodeWithText(String content, String text) {
        Map<EncodeHintType, Object> hints = new HashMap<>();
        hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
        try {
            // 生成矩阵
            BitMatrix bitMatrix = new MultiFormatWriter().encode(content,
                    BarcodeFormat.QR_CODE, IMG_WIDTH, IMG_HEIGHT, hints);
            BufferedImage image = pressText(text, MatrixToImageWriter.toBufferedImage(bitMatrix), Color.BLACK, FONT_SIZE, IMG_WIDTH, IMG_HEIGHT);
            ByteArrayOutputStream os = new ByteArrayOutputStream();
            ImageIO.write(image, "jpg", os);
            InputStream input = new ByteArrayInputStream(os.toByteArray());
            return new MockMultipartFile("file", "qrcode.jpg", "text/plain", input);
        } catch (WriterException | IOException exception) {
            throw new ApplicationException(exception.getMessage());
        }
    }

    public static BufferedImage pressText(String pressText, BufferedImage image, Color color, int fontSize, int width, int height) {

        //计算文字开始的位置
        //x开始的位置：（图片宽度-字体大小*字的个数）/2
        int startX = (width - (fontSize * pressText.length())) / 2;
        //y开始的位置：图片高度-（图片高度-图片宽度）/2
        int startY = height - (height - width) / 2 - 11;

        try {
            Graphics g = image.createGraphics();
            g.setColor(color);
            g.setFont(new Font("黑体", Font.PLAIN, fontSize));
            g.drawString(pressText, startX, startY);
            g.dispose();

            return image;
        } catch (Exception e) {
            System.out.println("1111" + e);
            return null;
        }
    }