尝试让eventHandler在自己的类中访问另一个类的方法

class ClassB {
    void methodB() {
        System.out.println("Method B");
    }
}

class ClassA {
    private ClassB classB;

    public ClassA(ClassB classB) {
        this.classB = classB;
    }

    void eventHandler() {
        // 访问ClassB的方法
        classB.methodB();
    }
}

public class Main {
    public static void main(String[] args) {
        ClassB b = new ClassB();
        ClassA a = new ClassA(b);
        a.eventHandler();
    }
}

interface Service {
    void execute();
}

class ServiceImpl implements Service {
    @Override
    public void execute() {
        System.out.println("Service implementation");
    }
}

class EventHandler {
    private Service service;

    public EventHandler(Service service) {
        this.service = service;
    }

    void handleEvent() {
        service.execute();
    }
}

public class Main {
    public static void main(String[] args) {
        Service service = new ServiceImpl();
        EventHandler handler = new EventHandler(service);
        handler.handleEvent();
    }
}

interface Shape {
    void draw();
}

class Circle implements Shape {
    @Override
    public void draw() {
        System.out.println("Drawing a circle");
    }
}

class Square implements Shape {
    @Override
 public void draw() {
        System.out.println("Drawing a square");
    }
}

class ShapeDrawer {
    private Shape shape;

    public ShapeDrawer(Shape shape) {
        this.shape = shape;
    }

    void drawShape() {
        shape.draw();
    }
}

public class Main {
    public static void main(String[] args) {
        Shape circle = new Circle();
        ShapeDrawer drawer = new ShapeDrawer(circle);
        drawer.drawShape();

        Shape square = new Square();
        drawer = new ShapeDrawer(square);
        drawer.drawShape();
    }
}