【JAVA学习之路 | 基础篇】方法的重写(Override)

public class GeometricObjectText {
    public static void main(String[] args) {
        GeometricObjectText g = new GeometricObjectText();
        Circle c = new Circle(1, "黑色", 1);
        MyRectangle m = new MyRectangle("绿色", 1, 2, 1);
        System.out.println(g.equalsArea(c, m));
        g.displayGeometricObject(c);
        g.displayGeometricObject(m);
    }
输出结果 ：
false
面积是3.141592653589793
黑色
面积是2.0
绿色
 
 
    public boolean equalsArea(GeometricObject c, GeometricObject m) {
        if (c.findArea() == m.findArea()) {
            return true;
        } else {
            return false;
        }
    }
    public void displayGeometricObject(GeometricObject g) {
        System.out.println("面积是" + g.findArea());
        System.out.println(g.getColor());
    }
}
 
public class GeometricObject {
    private String color;
    private double weight;
    public GeometricObject() {
 
    }
    public GeometricObject(String color, double weight) {
        this.color = color;
        this.weight = weight;
    }
 
    public String getColor() {
        return color;
    }
 
    public void setColor(String color) {
        this.color = color;
    }
 
    public double getWeight() {
        return weight;
    }
 
    public void setWeight(double weight) {
        this.weight = weight;
    }
    public double findArea() {
        return 1.0;
    }
}
 
public class Circle extends GeometricObject {
    private double radius;
    public Circle(double radius, String color, double weight) {
        super(color, weight);
        this.radius = radius;
    }
 
    public double getRadius() {
        return radius;
    }
 
    public void setRadius(double radius) {
        this.radius = radius;
    }
    //方法的重写
    public double findArea() {
        return (Math.PI) * radius * radius;
    }
}
 
public class MyRectangle extends GeometricObject {
    private double width;
    private double height;
 
    public MyRectangle(String color, double weight, double width, double height) {
        super(color, weight);
        this.width = width;
        this.height = height;
    }
 
    public double getWidth() {
        return width;
    }
 
    public void setWidth(double width) {
        this.width = width;
    }
 
    public double getHeight() {
        return height;
    }
 
    public void setHeight(double height) {
        this.height = height;
    }
    //方法的重写
    public double findArea() {
        return (width) * height;
    }
}