用java1.编写一个圆类，圆类有半径Radius和圆心心center等属性，这些属性可以查看get 也可以重新设置set,另外还可以统计圆的个数，返回其面积及周长。 2.编写一个圆环类 Ring。圆环类有内半径innerRadius,外半径outerRadius和圆心center等属性,这些属性可以查看get 也可以重新设置set,另外，圆环还可以返回其面积及外周长。 3.创建圆环类的对象，并输出对象的面积和周长;创建多个圆，输出总的个数，每个圆的面积周长等。

1. 圆类的代码如下：

public class Circle {
    private double radius;
    private Point center;
    private static int count = 0;

    public Circle(double radius, Point center) {
        this.radius = radius;
        this.center = center;
        count++;
    }

    public double getRadius() {
        return radius;
    }

    public void setRadius(double radius) {
        this.radius = radius;
    }

    public Point getCenter() {
        return center;
    }

    public void setCenter(Point center) {
        this.center = center;
    }

    public static int getCount() {
        return count;
    }

    public double getArea() {
        return Math.PI * radius * radius;
    }

    public double getPerimeter() {
        return 2 * Math.PI * radius;
    }
}

2. 圆环类的代码如下：

public class Ring {
    private double innerRadius;
    private double outerRadius;
    private Point center;

    public Ring(double innerRadius, double outerRadius, Point center) {
        this.innerRadius = innerRadius;
        this.outerRadius = outerRadius;
        this.center = center;
    }

    public double getInnerRadius() {
        return innerRadius;
    }

    public void setInnerRadius(double innerRadius) {
        this.innerRadius = innerRadius;
    }

    public double getOuterRadius() {
        return outerRadius;
    }

    public void setOuterRadius(double outerRadius) {
        this.outerRadius = outerRadius;
    }

    public Point getCenter() {
        return center;
    }

    public void setCenter(Point center) {
        this.center = center;
    }

    public double getArea() {
        return Math.PI * (outerRadius * outerRadius - innerRadius * innerRadius);
    }

    public double getPerimeter() {
        return 2 * Math.PI * (outerRadius + innerRadius);
    }
}

3. 创建圆环类的对象并输出面积和周长的代码如下：

Ring ring = new Ring(3, 5, new Point(0, 0));
System.out.println("Ring area: " + ring.getArea());
System.out.println("Ring perimeter: " + ring.getPerimeter());

创建多个圆并输出总个数、每个圆的面积和周长的代码如下：

Circle circle1 = new Circle(2, new Point(0, 0));
Circle circle2 = new Circle(3, new Point(1, 1));
Circle circle3 = new Circle(4, new Point(2, 2));

System.out.println("Total number of circles: " + Circle.getCount());

System.out.println("Circle 1 area: " + circle1.getArea());
System.out.println("Circle 1 perimeter: " + circle1.getPerimeter());

System.out.println("Circle 2 area: " + circle2.getArea());
System.out.println("Circle 2 perimeter: " + circle2.getPerimeter());

System.out.println("Circle 3 area: " + circle3.getArea());
System.out.println("Circle 3 perimeter: " + circle3.getPerimeter());