使用zxing生成和识别二维码

maven

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

        <!-- https://mvnrepository.com/artifact/com.google.zxing/javase -->
        <dependency>
            <groupId>com.google.zxing</groupId>
            <artifactId>javase</artifactId>
            <version>3.3.0</version>
        </dependency>

生成二维码

public static void generateQrCode(OutputStream out,String content, int width, int height, String format) throws WriterException, IOException {
        //format="png"
        Map<EncodeHintType, Object> hints = new HashMap<EncodeHintType, Object>();
        // 设置QR二维码的纠错级别（H为最高级别）具体级别信息
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
        // 内容所使用编码
        hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
        // 设置图片的边距
        hints.put(EncodeHintType.MARGIN,1);
        // 生成矩阵
        BitMatrix bitMatrix = new MultiFormatWriter().encode(content,
                BarcodeFormat.QR_CODE, width, height, hints);
        // 输出图像
        MatrixToImageWriter.writeToStream(bitMatrix,format,out);
    }

识别二维码

public static Result decodeQrCode(InputStream inputStream) throws IOException, NotFoundException {
        BufferedImage image = ImageIO.read(inputStream);
        LuminanceSource source = new BufferedImageLuminanceSource(image);
        Binarizer binarizer = new HybridBinarizer(source);
        BinaryBitmap binaryBitmap = new BinaryBitmap(binarizer);
        Map<DecodeHintType, Object> hints = new HashMap<DecodeHintType, Object>();
        hints.put(DecodeHintType.CHARACTER_SET, "UTF-8");
        Result result = new MultiFormatReader().decode(binaryBitmap, hints);// 对图像进行解码
        return result;
    }

doc

• 二维码的生成细节和原理
• QR码的信息量和版本
• 缺了一块的二维码，为什么也能扫描出来？
• 二维码的基础原理是什么？