java 使用zxing生成二维码,要求二维码上面生成可换行标题,返回BufferedImage

可以使用 zxing 的 MultiFormatWriter 类来生成二维码，要在二维码上方生成可换行标题，可以使用 BufferedImage 类来创建一个新的 BufferedImage 对象，并在上面绘制标题和二维码。具体代码如下：

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;

public class QRCodeUtil {
    /**
     * 生成带有标题的二维码
     *
     * @param content 二维码内容
     * @param title   标题
     * @param width   二维码宽度
     * @param height  二维码高度
     * @return 带有标题的二维码 BufferedImage 对象
     */
    public static BufferedImage createQRCodeWithTitle(String content, String title, int width, int height) {
        try {
            // 生成二维码矩阵
            BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, width, height);

            // 获取二维码图片的宽高
            int qrCodeWidth = bitMatrix.getWidth();
            int qrCodeHeight = bitMatrix.getHeight();

            // 新建一个 BufferedImage 对象
            BufferedImage image = new BufferedImage(qrCodeWidth, qrCodeHeight + 50, BufferedImage.TYPE_INT_RGB);

            // 在 BufferedImage 上绘制标题和二维码
            Graphics2D graphics = image.createGraphics();
            graphics.setColor(Color.WHITE);
            graphics.fillRect(0, 0, qrCodeWidth, qrCodeHeight + 50);
            graphics.setColor(Color.BLACK);
            graphics.setFont(new Font("宋体", Font.BOLD, 20));
            String[] titleLines = title.split("\n");
            int titleHeight = graphics.getFontMetrics().getHeight() * titleLines.length;
            for(int i = 0; i < titleLines.length; i++) {
                String titleLine = titleLines[i];
                int titleWidth = graphics.getFontMetrics().stringWidth(titleLine);
                int titleX = (qrCodeWidth - titleWidth) / 2;
                int titleY = qrCodeHeight + 15 + i * graphics.getFontMetrics().getHeight();
                graphics.drawString(titleLine, titleX, titleY);
            }
            QRCodeWriter qrCodeWriter = new QRCodeWriter();
            BitMatrix qrCodeMatrix = qrCodeWriter.encode(content, BarcodeFormat.QR_CODE, qrCodeWidth, qrCodeHeight);
            for (int y = 0; y < qrCodeHeight; y++) {
                int offset = y * qrCodeWidth;
                for (int x = 0; x < qrCodeWidth; x++) {
                    image.setRGB(x, y + titleHeight, qrCodeMatrix.get(x, y) ? 0xFF000000 : 0xFFFFFFFF);
                }
            }
            return image;
        } catch (WriterException e) {
            e.printStackTrace();
            return null;
        }
    }
}

调用方式：

BufferedImage image = QRCodeUtil.createQRCodeWithTitle("二维码内容", "标题\n换行", 400, 400);
ImageIO.write(image, "png", new File("qrcode.png"));