import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.awt.image.WritableRaster;
import java.net.URL;
import java.util.List;

/**
 * @program: test-wechatqrcode
 * @description: 微信二维码扫描opencv库方法调用
 * @author: test
 * @create: 221-08-21 17:05
 **/
public class WeChatQRCodeTool {
    private static volatile WeChatQRCodeTool instance;
    private static volatile org.opencv.wechat_qrcode.WeChatQRCode detector;
　　//封装程了工具类，所以做成了单例
    private WeChatQRCodeTool() {
        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
　　　　　//微信提供的4个模型配置文件放在resource/wechatqrcode文件夹里
        URL detectprototxt = ClassLoader.getSystemResource("wechatqrcode/detect.prototxt");
        URL detectcaffemodel = ClassLoader.getSystemResource("wechatqrcode/detect.caffemodel");
        URL srprototxt = ClassLoader.getSystemResource("wechatqrcode/sr.prototxt");
        URL srcaffemodel = ClassLoader.getSystemResource("wechatqrcode/sr.caffemodel");
　　　　 //实例化微信二维码扫描对象
        detector = new org.opencv.wechat_qrcode.WeChatQRCode(
                detectprototxt.getPath().substring(1),
                //substring1去掉/D:/xx里的/
                detectcaffemodel.getPath().substring(1),
                srprototxt.getPath().substring(1),
                srcaffemodel.getPath().substring(1));

    }

    public static WeChatQRCodeTool getInstance() {
        if (instance == null) {
            synchronized (WeChatQRCodeTool.class) {
                if (instance == null) {
                    instance = new WeChatQRCodeTool();
                }
            }
        }
        return instance;
    }

　　/**
    * 这里提供一个bufferimage的入参。如果是File对象，可以用ImageIO.read()获取一下bufferimage.
　　*/
    public String decode(BufferedImage srcImage) {
        Mat image = bufImg2Mat(srcImage, srcImage.getType(), CvType.CV_8UC3);
        //返回解析的字符串，如果图片有多个二维码，则会返回多个。
        List<String> result2 = detector.detectAndDecode(image);
        if (result2 != null && result2.size() > 0) {
            return result2.get(0);
        }
        return null;
    }


    /**
     * BufferedImage转换成Mat
     *
     * @param original 要转换的BufferedImage
     * @param imgType  bufferedImage的类型 如 BufferedImage.TYPE_3BYTE_BGR
     * @param matType  转换成mat的type 如 CvType.CV_8UC3
     */
    public static Mat bufImg2Mat(BufferedImage original, int imgType, int matType) {
        if (original == null) {
            throw new IllegalArgumentException("original == null");
        }

        // Don't convert if it already has correct type
        if (original.getType() != imgType) {

            // Create a buffered image
            BufferedImage image = new BufferedImage(original.getWidth(), original.getHeight(), imgType);

            // Draw the image onto the new buffer
            Graphics2D g = image.createGraphics();
            try {
                g.setComposite(AlphaComposite.Src);
                g.drawImage(original, 0, 0, null);
            } finally {
                g.dispose();
            }
        }

        byte[] pixels = ((DataBufferByte) original.getRaster().getDataBuffer()).getData();
        Mat mat = Mat.eye(original.getHeight(), original.getWidth(), matType);
        mat.put(0, 0, pixels);
        return mat;
    }

    /**
     *  Mat转换为BufferedImage
     */
    public static BufferedImage matToBufferedImage(Mat mat) {
        if (mat.height() > 0 && mat.width() > 0) {
            BufferedImage image = new BufferedImage(mat.width(), mat.height(),
                    BufferedImage.TYPE_3BYTE_BGR);
            WritableRaster raster = image.getRaster();
            DataBufferByte dataBuffer = (DataBufferByte) raster.getDataBuffer();
            byte[] data = dataBuffer.getData();
            mat.get(0, 0, data);
            return image;
        }

        return null;
    }

}

 由于wechatqrcode属于第三方扩展库，不属于opencv的主版本，所以opencv自带的发布dll和jar里没有。需要自编译。花了我一天时间。具体参考：

Windows下联合编译opencv+opencv_contrib微信二维码引擎_VQB01799的博客-CSDN博客

不想花费时间编译的，可以使用下面我分享到百度网盘的opencv_java453.dll链接库和opencv-453.jar