java - OpenCV java 人脸检测 NullPointerException

Question

我正在 mac 中学习 OpenCV java。我正在在线试用该教程，但在线程“主”java.lang.NullPointerException 中出现异常

这是我的代码

import org.opencv.core.*;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;
import org.opencv.objdetect.CascadeClassifier;


public class testApp {
    public static void main(String[] args) {
        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
        CascadeClassifier faceDetector = new CascadeClassifier(testApp.class
                        .getResource("/Users/myName/Downloads/opencv/data/haarcascades/haarcascade_frontalface_alt2.xml")
                        .getPath());

        Mat image = Imgcodecs.imread(testApp.class
                        .getResource("lena.png")
                        .getPath());

        MatOfRect faceD = new MatOfRect();
        faceDetector.detectMultiScale(image,faceD);
        for (Rect rect:faceD.toArray()){
            Imgproc.rectangle(image,new Point(rect.x,rect.y),new Point(rect.x+rect.width,rect.y+rect.height),
                    new Scalar(0,255,0));
        }

        String outputFile = "OUTPUT.png";
        //System.out.println(String.format("writing %s", outputFile));
        Imgcodecs.imwrite(outputFile,image);

    }
}

错误

Exception in thread "main" java.lang.NullPointerException
    at testApp.main(testApp.java:13)

请问如何解决，谢谢

Answer 1

好像.getResource("/Users/myName/Downloads/opencv/data/haarcascades/haarcascade_frontalface_alt2.xml")返回null，因为找不到资源。因此，我建议您检查上面的路径是否正确。