java生成二维码以及二维码的解码

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1.依赖

    <!--二维码-->
    <dependency>
      <groupId>com.google.zxing</groupId>
      <artifactId>core</artifactId>
      <version>3.3.0</version>
    </dependency>
    <dependency>
      <groupId>com.google.zxing</groupId>
      <artifactId>javase</artifactId>
      <version>3.3.0</version>
    </dependency>

2.BufferedImageLuminanceSource类

import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import com.google.zxing.LuminanceSource;

public class BufferedImageLuminanceSource extends LuminanceSource {

    private final BufferedImage image;
    private final int left;
    private final int top;

    public BufferedImageLuminanceSource(BufferedImage image) {
        this(image, 0, 0, image.getWidth(), image.getHeight());
    }

    public BufferedImageLuminanceSource(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;
    }

    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;
    }

    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;
    }

    public boolean isCropSupported() {
        return true;
    }

    public LuminanceSource crop(int left, int top, int width, int height) {
        return new BufferedImageLuminanceSource(image, this.left + left, this.top + top, width, height);
    }

    public boolean isRotateSupported() {
        return true;
    }

    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 BufferedImageLuminanceSource(rotatedImage, top, sourceWidth - (left + width), getHeight(), width);
    }

}

3.QRCodeUtil类

import java.awt.BasicStroke;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Shape;
import java.awt.geom.RoundRectangle2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.OutputStream;
import java.util.Hashtable;
import java.util.Random;
import javax.imageio.ImageIO;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.EncodeHintType;
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;

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);
        // String file = new Random().nextInt(99999999)+".jpg";
        // ImageIO.write(image, FORMAT_NAME, new File(destPath+"/"+file));
        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);
    }
    // 被注释的方法
    /*
     * public static void encode(String content, String destPath, boolean
     * needCompress) throws Exception { QRCodeUtil.encode(content, null, destPath,
     * needCompress); }
     */

    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));
    }

}

4.使用

public class QrCodeTest {
    public static void main(String[] args) throws Exception {
        // 存放在二维码中的内容
        String text = "二维码的内容";
        // 嵌入二维码的图片路径 null表示不在二维码中插入自己的图片
        String imgPath = null;
        // 生成的二维码的路径及名称
        String destPath = "E:/xx.jpg";
        //生成二维码
        QRCodeUtil.encode(text, imgPath, destPath, true);
        // 解析二维码
        String str = QRCodeUtil.decode(destPath);
        // 打印出解析出的内容
        System.out.println(str);
    }
}

5.在JavaWeb中使用

5.1 生成二维码

	//生成二维码
    private void makeQrCode(HttpServletRequest request, HttpServletResponse response) {
        // ..... 业务逻辑

		//可配置扫码后跳转的页面
		String text = "http://localhost:8081/#/verify/success";
		// 生成的二维码的路径及名称
		String destPath = "E:/xxx.jpg";
		//生成二维码
		QRCodeUtil.encode(text, null, destPath, true);
		
		// ..... 向前端响应成功与失败信息
    }

5.2 展示验证码到页面

	//获得二维码
    private void getVerify(HttpServletRequest request, HttpServletResponse response) {
        // ..... 处理验证的业务逻辑
        
        try {
            String filePath = "E:/xxx.jpg";
            FileInputStream fis = new FileInputStream(filePath);
            //创建一个输出流到浏览器
            response.setContentType("image/png");
            ServletOutputStream out = response.getOutputStream();

            int length = 0;
            byte[] buffer = new byte[1024];
            while ((length = fis.read(buffer)) != -1){
                out.write(buffer);
            }

            fis.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

5.3 前端

<img :src="verifyImg" />
-----------------------------------------------------------
    data() {
      return {
        verifyImg: '',
      }
    },
-----------------------------------------------------------
createQrCode() {
        let data = {
          //...你需要携带的数据
        }
        makeQrCode(data).then((res) => {
          //当生成验证成功后，请求获取验证码的图片
          axios
            .get('http://localhost:8080/equip/getVerify', {
              params: {
                // .... 需要携带的参数
              },
              responseType: 'arraybuffer',
            })
            .then((response) => {
              return (
                'data:image/png;base64,' +
                btoa(
                  new Uint8Array(response.data).reduce(
                    (data, byte) => data + String.fromCharCode(byte),
                    ''
                  )
                )
              )
            })
            .then((data) => {
              //保存图片
              this.verifyImg = data
            })
        })
      },

export function makeQrCode(data) {
  return request({
    url: 'http://localhost:8080/xxx/makeQrCode',
    method: 'post',
    data,
  })
}

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Java教程

java生成二维码以及二维码的解码

1.依赖

2.BufferedImageLuminanceSource类

3.QRCodeUtil类

4.使用

5.在JavaWeb中使用

5.1 生成二维码

5.2 展示验证码到页面

5.3 前端

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