Java计算几何图形面积的实例代码

public abstract class Shape {
    public String getName() {//获得图形的名称
        return this.getClass().getSimpleName();
    }
    public abstract double getArea();//获得图形的面积
}
public class Circle extends Shape {
    private double radius;
    public Circle(double radius) {//获得圆形的半径
        this.radius = radius;
    }
    @Override
    public double getArea() {//计算圆形的面积
        return Math.PI * Math.pow(radius, 2);
    }
}
public class Rectangle extends Shape {
    private double length;
    private double width;
    public Rectangle(double length, double width) {//获得矩形的长和宽
        this.length = length;
        this.width = width;
    }
    @Override
    public double getArea() {//计算矩形的面积
        return length * width;
    }
}
public class Test {
    public static void main(String[] args) {
        Circle circle = new Circle(1);//创建圆形对象并将半径设置成1
        System.out.println("图形的名称是：" + circle.getName());
        System.out.println("图形的面积是：" + circle.getArea());
        Rectangle rectangle = new Rectangle(1, 1);//创建矩形对象并将长和宽设置成1
        System.out.println("图形的名称是：" + rectangle.getName());
        System.out.println("图形的面积是：" + rectangle.getArea());
    }
}