Java生成图片二维码并下载

最新推荐文章于 2025-07-27 13:42:38 发布

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最新推荐文章于 2025-07-27 13:42:38 发布

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分类专栏： java小知识文章标签： java qrcode 下载二维码

本文链接：https://blog.youkuaiyun.com/weixin_41245089/article/details/88190175

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2 篇文章

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本文介绍了如何在Java中生成二维码并提供下载功能。首先，文章提到需要导入相关依赖。接着，详细阐述了一个名为`qrcodeutils`的工具类的实现。在实际应用中，通过控制器方法调用这个工具类，完成二维码的生成，并设置响应头以实现二维码图片的下载。

1.导入依赖

<dependency>
    <groupId>com.google.zxing</groupId>
    <artifactId>core</artifactId>
    <version>3.3.0</version>
</dependency>

2.工具类qrcodeutils

public class QrcodeUtils {
    public static void downloadQrcode(String content, HttpServletResponse response, HttpServletRequest request) throws Exception {
        //转换字符，避免中文乱码问题
        content = new String(content.getBytes("UTF-8"),"ISO-8859-1");

        Hashtable<EncodeHintType, ErrorCorrectionLevel> hintMap = new Hashtable<EncodeHintType, ErrorCorrectionLevel>();
        hintMap.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);  // 矫错级别
        QRCodeWriter qrCodeWriter = new QRCodeWriter();
        //创建比特矩阵(位矩阵)的QR码编码的字符串
        BitMatrix byteMatrix = qrCodeWriter.encode(content, BarcodeFormat.QR_CODE, 900, 900, hintMap);
        // 使BufferedImage勾画QRCode  (matrixWidth 是行二维码像素点)
        int matrixWidth = byteMatrix.getWidth();
        BufferedImage image = new BufferedImage(900, 900, BufferedImage.TYPE_INT_RGB);
        image.createGraphics();
        Graphics2D graphics = (Graphics2D) image.getGraphics();
        graphics.setColor(Color.WHITE);
        graphics.fillRect(0, 0, matrixWidth, matrixWidth);
        // 使用比特矩阵画并保存图像
        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, j, 1, 1);
                }
            }
        }

        /**
         * 将image转换成流
         */
        response.setHeader("Content-Type","application/octet-stream");
        response.setHeader("Content-Disposition","attachment;filename=qrcode.jpg");
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ImageIO.write(image, "JPEG", baos);
        baos.flush();
        byte[] imageInByte = baos.toByteArray();
        baos.close();

        response.getOutputStream().write(imageInByte);

        response.getOutputStream().flush();

        response.getOutputStream().close();

    }
}

3.使用

3.1控制器：

@GetMapping("/downLoadQrcode")
public ResultBean<Void> downLoadQrcode(Long shopId, HttpServletResponse response, HttpServletRequest request){
    try {
        qrcoceBusiness.downloadQrcode("http://wx1.great-info.tech/?shopId="+shopId,response,request);
    } catch (Exception e) {
        e.printStackTrace();
        return new ResultBean<>(ServiceCode.DELETE_FAILURE,ServiceCode.DELETE_FAILURE_MSG);
    }
    return new ResultBean<>(ServiceCode.OK,ServiceCode.OK_DEFAULT_MSG);
}

3.2调用utils

public void downloadQrcode(String content, HttpServletResponse response, HttpServletRequest request) throws Exception {
    QrcodeUtils.downloadQrcode(content,response,request);
}