【java】生成二维码的util

墨蓝 2022-03-25 12:12 114阅读 0赞

这两天接到了一个生成二维码的需求，和大家分享一下用工具生成二维码的快感：

1、首先我们需要在maven中引入依赖：

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

2、粘入QRutil的代码

import java.awt.Graphics2D;
    import java.awt.geom.AffineTransform;
    import java.awt.image.BufferedImage;
    import java.io.File;
    import java.io.IOException;
    import java.io.OutputStream;
    import java.util.HashMap;
    import java.util.Hashtable;
    import java.util.Map;
    import java.util.Random;
    
    import javax.imageio.ImageIO;
    import javax.servlet.http.HttpServletResponse;
     
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
     
    import com.google.zxing.BarcodeFormat;
    import com.google.zxing.Binarizer;
    import com.google.zxing.BinaryBitmap;
    import com.google.zxing.DecodeHintType;
    import com.google.zxing.EncodeHintType;
    import com.google.zxing.LuminanceSource;
    import com.google.zxing.MultiFormatReader;
    import com.google.zxing.MultiFormatWriter;
    import com.google.zxing.Result;
    import com.google.zxing.common.BitMatrix;
    import com.google.zxing.common.HybridBinarizer;
    import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
     
    /**
     * <p>Title:QRCodeUtil </p>
     * <p>Description: 二维码生成工具类</p>
     * @author Administrator
     * @version 
     * @since 
     */
    public final class QRCodeUtil extends LuminanceSource {
     
        private static final Logger logger = LoggerFactory.getLogger(QRCodeUtil.class);
     
        // 二维码颜色
        private static final int BLACK = 0xFF000000;
        // 二维码颜色
        private static final int WHITE = 0xFFFFFFFF;
     
        private final BufferedImage image;
        private final int left;
        private final int top;
     
        public QRCodeUtil(BufferedImage image) {
            this(image, 0, 0, image.getWidth(), image.getHeight());
        }
     
        public QRCodeUtil(BufferedImage image, int left, int top, int width, int height) {
            super(width, height);
            int sourceWidth = image.getWidth();
            int sourceHeight = image.getHeight();
            if (left + width > sourceWidth || top + height > sourceHeight) {
                throw new IllegalArgumentException("Crop rectangle does not fit within image data.");
            }
            for (int y = top; y < top + height; y++) {
                for (int x = left; x < left + width; x++) {
                    if ((image.getRGB(x, y) & 0xFF000000) == 0) {
                        image.setRGB(x, y, 0xFFFFFFFF); // = white
                    }
                }
            }
            this.image = new BufferedImage(sourceWidth, sourceHeight, BufferedImage.TYPE_BYTE_GRAY);
            this.image.getGraphics().drawImage(image, 0, 0, null);
            this.left = left;
            this.top = top;
        }
     
        @Override
        public byte[] getRow(int y, byte[] row) {
            if (y < 0 || y >= getHeight()) {
                throw new IllegalArgumentException("Requested row is outside the image: " + y);
            }
            int width = getWidth();
            if (row == null || row.length < width) {
                row = new byte[width];
            }
            image.getRaster().getDataElements(left, top + y, width, 1, row);
            return row;
        }
     
        @Override
        public byte[] getMatrix() {
            int width = getWidth();
            int height = getHeight();
            int area = width * height;
            byte[] matrix = new byte[area];
            image.getRaster().getDataElements(left, top, width, height, matrix);
            return matrix;
        }
     
        @Override
        public boolean isCropSupported() {
            return true;
        }
     
        @Override
        public LuminanceSource crop(int left, int top, int width, int height) {
            return new QRCodeUtil(image, this.left + left, this.top + top, width, height);
        }
     
        @Override
        public boolean isRotateSupported() {
            return true;
        }
     
        @Override
        public LuminanceSource rotateCounterClockwise() {
            int sourceWidth = image.getWidth();
            int sourceHeight = image.getHeight();
            AffineTransform transform = new AffineTransform(0.0, -1.0, 1.0, 0.0, 0.0, sourceWidth);
            BufferedImage rotatedImage = new BufferedImage(sourceHeight, sourceWidth, BufferedImage.TYPE_BYTE_GRAY);
            Graphics2D g = rotatedImage.createGraphics();
            g.drawImage(image, transform, null);
            g.dispose();
            int width = getWidth();
            return new QRCodeUtil(rotatedImage, top, sourceWidth - (left + width), getHeight(), width);
        }
     
        /**
         * @param matrix
         * @return
         */
        private static BufferedImage toBufferedImage(BitMatrix matrix) {
            int width = matrix.getWidth();
            int height = matrix.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, matrix.get(x, y) ? BLACK : WHITE);
                }
            }
            return image;
        }
     
        /**
         * 生成二维码图片
         * 
         * @param matrix
         * @param format
         * @param file
         * @throws IOException
         */
        public static void writeToFile(BitMatrix matrix, String format, File file) throws IOException {
            BufferedImage image = toBufferedImage(matrix);
            if (!ImageIO.write(image, format, file)) {
                throw new IOException("Could not write an image of format " + format + " to " + file);
            }
        }
     
        /**
         * 生成二维码图片流
         * 
         * @param matrix
         * @param format
         * @param stream
         * @throws IOException
         */
        public static void writeToStream(BitMatrix matrix, String format, OutputStream stream) throws IOException {
            BufferedImage image = toBufferedImage(matrix);
            if (!ImageIO.write(image, format, stream)) {
                throw new IOException("Could not write an image of format " + format);
            }
        }
     
        /**
         * 根据内容，生成指定宽高、指定格式的二维码图片
         *
         * @param text   内容
         * @param width  宽
         * @param height 高
         * @param format 图片格式
         * @return 生成的二维码图片路径
         * @throws Exception
         */
        private static String generateQRCode(String text, int width, int height, String format, String pathName)
                throws Exception {
            Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
            hints.put(EncodeHintType.CHARACTER_SET, "utf-8");// 指定编码格式
            hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);// 指定纠错等级
            hints.put(EncodeHintType.MARGIN, 1); // 白边大小，取值范围0~4
            BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);
            File outputFile = new File(pathName);
            writeToFile(bitMatrix, format, outputFile);
            return pathName;
        }
     
        /**
         * 输出二维码图片流
         * 
         * @param text 二维码内容
         * @param width 二维码宽
         * @param height 二维码高
         * @param format 图片格式eg: png, jpg, gif
         * @param response HttpServletResponse
         * @throws Exception
         */
        public static void generateQRCode(String text, int width, int height, String format, HttpServletResponse response)
                throws Exception {
            Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
            hints.put(EncodeHintType.CHARACTER_SET, "utf-8");// 指定编码格式
            hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);// 指定纠错等级
            hints.put(EncodeHintType.MARGIN, 1); // 白边大小，取值范围0~4
            BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);
            writeToStream(bitMatrix, format, response.getOutputStream());
        }
     
        /**
         * 解析指定路径下的二维码图片
         *
         * @param filePath 二维码图片路径
         * @return
         */
        public static String parseQRCode(String filePath) {
            String content = "";
            try {
                File file = new File(filePath);
                BufferedImage image = ImageIO.read(file);
                LuminanceSource source = new QRCodeUtil(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");
                MultiFormatReader formatReader = new MultiFormatReader();
                Result result = formatReader.decode(binaryBitmap, hints);
     
                logger.info("result 为：" + result.toString());
                logger.info("resultFormat 为：" + result.getBarcodeFormat());
                logger.info("resultText 为：" + result.getText());
                // 设置返回值
                content = result.getText();
            } catch (Exception e) {
                logger.error(e.getMessage());
            }
            return content;
        }
     
        public static void main(String[] args) {
            String text = "王啸"; // 随机生成验证码
            System.out.println("随机码： " + text);
            int width = 200; // 二维码图片的宽
            int height = 200; // 二维码图片的高
            String format = "png"; // 二维码图片的格式
    
            try {
                // 生成二维码图片，并返回图片路径
                String pathName = generateQRCode(text, width, height, format, "D:/new.png");
                System.out.println("生成二维码的图片路径： " + pathName);
    
                String content = parseQRCode(pathName);
                System.out.println("解析出二维码的图片的内容为： " + content);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
     
    }

我们可以看到，这个util中的main方法中提供的示例包含了生成和读取两种方式的代码，我们如果只是生成的话，可以简化成这样：

public static String getQRcode(String text){
       String format = "png"; // 二维码图片的格式
       String fileName="qrCode"+System.currentTimeMillis()+new Random().nextInt(1000)+"."+format;
       int width = 300; // 二维码图片的宽
       int height = 300; // 二维码图片的高
       try {
           generateQRCode(text, width, height, format, fileName);
       }catch (Exception e){
           logger.error("生成二维码失败",e);
       }
       return fileName;
    }

入参为二维码内容，返回值为生成二维码的文件路径，这样就很方便使用了，文件名字，用了字母+时间戳+1000内随机数构成，可以防止多线程访问的文件覆盖了。

分享一下我们二维码的生成之后的拿取和访问策略：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RyMTkxMg_size_16_color_FFFFFF_t_70][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RyMTkxMg_size_16_color_FFFFFF_t_70]: /images/20220325/aea69bb12d9b4b13a805a41aea99711c.png