为什么在尝试运行JavaFx应用程序时出现java.lang.ClassNotFoundException? [英] Why do I have java.lang.ClassNotFoundException while trying to run JavaFx application?

问题描述

我已尝试按照此处创建示例应用程序，代码是这样的:

I have tried to create example application as described here and the code is this:

package colorfulcircles;

import javafx.animation.KeyFrame;
import javafx.animation.KeyValue;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.effect.BlendMode;
import javafx.scene.effect.BoxBlur;
import javafx.scene.paint.Color;
import javafx.scene.paint.CycleMethod;
import javafx.scene.paint.LinearGradient;
import javafx.scene.paint.Stop;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Rectangle;
import javafx.scene.shape.StrokeType;
import javafx.stage.Stage;
import javafx.util.Duration;
import static java.lang.Math.random;


public class ColorfulCircles extends Application {

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage primaryStage) {
        Group root = new Group();
        Scene scene = new Scene(root, 800, 600, Color.BLACK);
        primaryStage.setScene(scene);
        Group circles = new Group();
        for (int i = 0; i < 30; i++) {
            Circle circle = new Circle(150, Color.web("white", 0.05));
            circle.setStrokeType(StrokeType.OUTSIDE);
            circle.setStroke(Color.web("white", 0.16));
            circle.setStrokeWidth(4);
            circles.getChildren().add(circle);
        }
        Rectangle colors = new Rectangle(scene.getWidth(), scene.getHeight(),
                new LinearGradient(0f, 1f, 1f, 0f, true, CycleMethod.NO_CYCLE, new Stop[]{
                    new Stop(0, Color.web("#f8bd55")),
                    new Stop(0.14, Color.web("#c0fe56")),
                    new Stop(0.28, Color.web("#5dfbc1")),
                    new Stop(0.43, Color.web("#64c2f8")),
                    new Stop(0.57, Color.web("#be4af7")),
                    new Stop(0.71, Color.web("#ed5fc2")),
                    new Stop(0.85, Color.web("#ef504c")),
                    new Stop(1, Color.web("#f2660f")),}));
        Group blendModeGroup =
                new Group(new Group(new Rectangle(scene.getWidth(), scene.getHeight(),
                     Color.BLACK), circles), colors);
        colors.setBlendMode(BlendMode.OVERLAY);
        root.getChildren().add(blendModeGroup);      
        circles.setEffect(new BoxBlur(10, 10, 3));
        Timeline timeline = new Timeline();
        for (Node circle : circles.getChildren()) {
            timeline.getKeyFrames().addAll(
                    new KeyFrame(Duration.ZERO, // set start position at 0
                    new KeyValue(circle.translateXProperty(), random() * 800),
                    new KeyValue(circle.translateYProperty(), random() * 600)),
                    new KeyFrame(new Duration(40000), // set end position at 40s
                    new KeyValue(circle.translateXProperty(), random() * 800),
                    new KeyValue(circle.translateYProperty(), random() * 600)));
        }
        // play 40s of animation
        timeline.play();
        primaryStage.show();
    }
}

为什么会出现异常? 我使用NetBeans 7.1 RC1 这是屏幕截图.

Why am I getting Exception? I use NetBeans 7.1 RC1 Here is the screenshot.

输出:

java.lang.ClassNotFoundException: javafxapplication4.JavaFXApplication4
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:264)
    at com.javafx.main.Main.getAppClass(Main.java:409)
    at com.javafx.main.Main.launchApp(Main.java:435)
    at com.javafx.main.Main.main(Main.java:537)

这个吗?

推荐答案

根据我在此屏幕快照中看到的内容，只是一个疯狂的猜测:您已重命名应用程序的主类，而Netbeans是还在寻找旧的类名来运行它?

Just a wild guess based on what I can see in this screen shot: You renamed the main class of your application and Netbeans is still looking for the old class name to run it?

尝试右键单击您的项目，然后在弹出的窗口中的运行"下查看主类".

Try right clicking your project, and looking at the "Main Class" under "Run" in the window that pops up.

否则，请发布堆栈跟踪本身，而不是其屏幕截图.

Otherwise, please post the stack trace itself, not a screen shot of it.

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