二维码生成

controller

public void getTrainSignQRCode(QRCodeDto qrCodeDto, HttpServletRequest request, HttpServletResponse response) throws Exception {
        //拼接参数
        HashMap<String, Object> map = new HashMap<>();
        map.put("id",qrCodeDto.getId());
        map.put("source",qrCodeDto.getSource());
        String content = JSON.toJSONString(map);
        commonService.getTrainSignQRCode(content, request, response);
      
    }

impl

public void getTrainSignQRCode(String content, HttpServletRequest request, HttpServletResponse response) throws Exception {
        //二维码中包含的信息
        Map<EncodeHintType, Object> hints = new HashMap<EncodeHintType, Object>();
        // 指定编码格式
        hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");

        //下面是毫秒级的时间戳
        String tempPath = name.format(new Date());
        // 获取文件路径  本地使用
        String path = System.getProperty("user.dir");
        String url = path+"/qrcode";
        File pathFile = new File(path+"/qrcode"+File.separator+tempPath);
        // 指定纠错级别(L--7%,M--15%,Q--25%,H--30%)
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
        // try {
        // 编码内容,编码类型(这里指定为二维码),生成图片宽度,生成图片高度,设置参数
        BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, 200, 200, hints);
        //设置请求头
        response.setCharacterEncoding("UTF-8");
        response.setHeader("Content-Type", "application/octet-stream");
        //设置输出时的名称
        response.setHeader("Content-Disposition", "attachment;filename=" + tempPath + ".png");
        String name = pathFile + ".png";
        Path file = new File(name).toPath();
        MatrixToImageWriter.writeToPath(bitMatrix, "png", file);
        QRCode.ioReadImage(url,file.toString(), response);
    

 public static void ioReadImage(String url,String imgUrl, HttpServletResponse response) throws Exception {
        ServletOutputStream out = null;
        FileInputStream ips = null;
        try {
            String imgPath = imgUrl;
            ips = new FileInputStream(new File(imgPath));
            String type = imgUrl.substring(imgUrl.indexOf(".") + 1);
            if (type.equals("png")) {
                response.setContentType("image/png");
            }
            if (type.equals("jpeg") || type.equals("jpg")) {
                response.setContentType("image/jpeg");
            }
            out = response.getOutputStream();
            //读取文件流
            int len = 0;
            byte[] buffer = new byte[1024 * 10];
            while ((len = ips.read(buffer)) != -1) {
                out.write(buffer, 0, len);
            }
            out.flush();

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            out.close();
            ips.close();
            delAllFile(url);
        }
    }

    //删除指定文件夹下所有文件
//param path 文件夹完整绝对路径
    public static boolean delAllFile(String path) {
        boolean flag = false;
        File file = new File(path);
        if (!file.exists()) {
            return flag;
        }
        if (!file.isDirectory()) {
            return flag;
        }
        String[] tempList = file.list();
        File temp = null;
        for (int i = 0; i < tempList.length; i++) {
            if (path.endsWith(File.separator)) {
                temp = new File(path + tempList[i]);
            } else {
                temp = new File(path + File.separator + tempList[i]);
            }
            if (temp.isFile()) {
                temp.delete();
            }
            if (temp.isDirectory()) {
                delAllFile(path + "/" + tempList[i]);//先删除文件夹里面的文件
                delFolder(path + "/" + tempList[i]);//再删除空文件夹
                flag = true;
            }
        }
        return flag;
    }