标签：java String image 新页面 imgPath content 二维码 跳转 return

java实现手机扫描二维码后网站跳转新页面，提供zxing和hutools的方式实现二维码的生成，动态刷新，验证跳转功能。

1.效果图：

二维码设置有效时间

失效重新获取二维码

手机扫描二维码成功后网站跳转新页面

 2.后端代码：

/**
 * @description 二维码控制器
 */
@Controller
public class QrcodeController {

    @Autowired
    private RedisUtils redisUtils;

    /**
     * @description 二维码页面
     * @return  java.lang.String
     **/
    @GetMapping({"/","/index"})
    public  String index(ModelMap modelMap){
        modelMap.put("userId", 1);
        return "index";
    }

    /**
     * @description 生成二维码
     * @param  request
     * @Param  response
     * @return  void
     **/
    @GetMapping("/getQrcode")
    @ResponseBody
    public void getQrcode(HttpServletRequest request, HttpServletResponse response) throws Exception {
        //二维码中的链接，需要公网网址才可以用手机扫描出来，本地测试开通natapp进行内网渗透
        String url = "http://qh22wg.natappfree.cc/scanQrcode";
        //过期时间，30s
        long expireTime = 30;
        //设置参数
        String random = request.getParameter("random");
        String userId = request.getParameter("userId");
        //生成二维码唯一标识
        String key = String.valueOf(System.currentTimeMillis());
        //设置二维码过期时间
        redisUtils.set(key,random,expireTime);
        //二维码中的内容
        String content = url + "?key=" + key + "&userId=" + userId;
        //二维码图片中间logo
        String imgPath = null;
        Boolean needCompress = true;
        //拿到图片流
        ByteArrayOutputStream out = QRCodeUtil.encodeIO(content, imgPath, needCompress);
        //返回二维码
        response.setCharacterEncoding("UTF-8");
        response.setContentType("image/jpeg;charset=UTF-8");
        response.setContentLength(out.size());
        ServletOutputStream outputStream = response.getOutputStream();
        outputStream.write(out.toByteArray());
        outputStream.flush();
        outputStream.close();
    }

   /**
    * @description 扫描二维码
    * @param  request
    * @Param  key
    * @Param  userId
    * @return  java.lang.String
    **/
    @GetMapping("/scanQrcode")
    @ResponseBody
    public String scanQrcode(HttpServletRequest request, String key, String userId) throws Exception {
        if(redisUtils.exists(key)){
            redisUtils.set(userId + "_qrcode_status", "success");
            return "扫描成功";
        }
        return "二维码失效, 请重新扫描";
    }

    /**
     * @description 验证扫描二维码
     * @param  userId
     **/
    @RequestMapping("/confirmQrcode")
    @ResponseBody
    public AjaxResult confirmQrcode(String userId){
        if(redisUtils.exists(userId + "_qrcode_status")){
            redisUtils.remove(userId + "_qrcode_status");
            //扫描成功后跳转新链接
            return AjaxResult.success("扫描成功", "/success");
        }
        return AjaxResult.error("二维码失效, 请重新扫描");
    }

    /**
     * @description 扫描二维码成功跳转页面
     * @param
     * @return  java.lang.String
     **/
    @GetMapping("/success")
    public  String success(ModelMap modelMap){
        return "success";
    }

}

zxing生成二维码工具：

public class QRCodeUtil {
    private static final String CHARSET = "utf-8";
    private static final String FORMAT_NAME = "JPG";
    // 二维码尺寸
    private static final int QRCODE_SIZE = 300;
    // LOGO宽度
    private static final int WIDTH = 60;
    // LOGO高度
    private static final int HEIGHT = 60;



    private static BufferedImage createImage(String content, String imgPath, boolean needCompress) throws Exception {
        Hashtable hints = new Hashtable();
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
        hints.put(EncodeHintType.CHARACTER_SET, CHARSET);
        hints.put(EncodeHintType.MARGIN, 1);
        BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, QRCODE_SIZE, QRCODE_SIZE,
                hints);
        int width = bitMatrix.getWidth();
        int height = bitMatrix.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, bitMatrix.get(x, y) ? 0xFF000000 : 0xFFFFFFFF);
            }
        }
        if (imgPath == null || "".equals(imgPath)) {
            return image;
        }
        // 插入图片
        QRCodeUtil.insertImage(image, imgPath, needCompress);
        return image;
    }

    private static void insertImage(BufferedImage source, String imgPath, boolean needCompress) throws Exception {
        File file = new File(imgPath);
        if (!file.exists()) {
            System.err.println("" + imgPath + "   该文件不存在！");
            return;
        }
        Image src = ImageIO.read(new File(imgPath));
        int width = src.getWidth(null);
        int height = src.getHeight(null);
        if (needCompress) { // 压缩LOGO
            if (width > WIDTH) {
                width = WIDTH;
            }
            if (height > HEIGHT) {
                height = HEIGHT;
            }
            Image image = src.getScaledInstance(width, height, Image.SCALE_SMOOTH);
            BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics g = tag.getGraphics();
            g.drawImage(image, 0, 0, null); // 绘制缩小后的图
            g.dispose();
            src = image;
        }
        // 插入LOGO
        Graphics2D graph = source.createGraphics();
        int x = (QRCODE_SIZE - width) / 2;
        int y = (QRCODE_SIZE - height) / 2;
        graph.drawImage(src, x, y, width, height, null);
        Shape shape = new RoundRectangle2D.Float(x, y, width, width, 6, 6);
        graph.setStroke(new BasicStroke(3f));
        graph.draw(shape);
        graph.dispose();
    }

    public static void encode(String content, String imgPath, String destPath, boolean needCompress) throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath, needCompress);
        mkdirs(destPath);
        ImageIO.write(image, FORMAT_NAME, new File(destPath));
    }

    public static BufferedImage encode(String content, String imgPath, boolean needCompress) throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath, needCompress);
        return image;
    }

    public static void mkdirs(String destPath) {
        File file = new File(destPath);
        // 当文件夹不存在时，mkdirs会自动创建多层目录，区别于mkdir．(mkdir如果父目录不存在则会抛出异常)
        if (!file.exists() && !file.isDirectory()) {
            file.mkdirs();
        }
    }

    public static void encode(String content, String imgPath, String destPath) throws Exception {
        QRCodeUtil.encode(content, imgPath, destPath, false);

    }

    public static byte[] getQRCodeImage(String content) throws WriterException, IOException {
        QRCodeWriter qrCodeWriter = new QRCodeWriter();
        BitMatrix bitMatrix = qrCodeWriter.encode(content, BarcodeFormat.QR_CODE, QRCODE_SIZE, QRCODE_SIZE);
        ByteArrayOutputStream pngOutputStream = new ByteArrayOutputStream();
        MatrixToImageWriter.writeToStream(bitMatrix, FORMAT_NAME, pngOutputStream);
        byte[] pngData = pngOutputStream.toByteArray();
        return pngData;
    }

    public static void encode(String content, String destPath) throws Exception {
        QRCodeUtil.encode(content, null, destPath, false);
    }

    public static void encode(String content, String imgPath, OutputStream output, boolean needCompress)
            throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath, needCompress);
        ImageIO.write(image, FORMAT_NAME, output);
    }

    public static void encode(String content, OutputStream output) throws Exception {
        QRCodeUtil.encode(content, null, output, false);
    }

    public static String decode(File file) throws Exception {
        BufferedImage image;
        image = ImageIO.read(file);
        if (image == null) {
            return null;
        }
        BufferedImageLuminanceSource source = new BufferedImageLuminanceSource(image);
        BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
        Result result;
        Hashtable hints = new Hashtable();
        hints.put(DecodeHintType.CHARACTER_SET, CHARSET);
        result = new MultiFormatReader().decode(bitmap, hints);
        String resultStr = result.getText();
        return resultStr;
    }

    public static String decode(String path) throws Exception {
        return QRCodeUtil.decode(new File(path));
    }

    //获取生成二维码的图片流
    public static ByteArrayOutputStream encodeIO(String content,String imgPath,Boolean needCompress) throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath,
                needCompress);
        //创建储存图片二进制流的输出流
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        //将二进制数据写入ByteArrayOutputStream
        ImageIO.write(image, "jpg", baos);
        return baos;
    }
}

3.demo下载：https://download.csdn.net/download/weixin_39220472/33632560

标签：java,String,image,新页面,imgPath,content,二维码,跳转,return
来源： https://blog.csdn.net/weixin_39220472/article/details/120888956

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