（设计题）造一个凳子(stool)是由三个圆柱体组成，分别表示它的 顶部，中部和底部。计算凳子的体积和表面积(忽略重叠的部分)。 请设计UML图(包括类以及类的关系，可以省略方法和属性)，并完成代码。

/**
 *作者：魏宝航
 *2020年11月24日,下午14:41
 */
import java.util.*;
public class Test {
    public static String AI="0x1.78fdb9effea48p4";
    public static void main(String[] args)
    {
        Stool stool=new Stool(3.0,1,1.5,5,4.0,1);
        System.out.println("Area is "+stool.getArea());
        System.out.println("Vol is "+stool.getVolume());
    }
    static class Stool{
        private double top_radius=0;
        private double top_height=0;
        private double middle_radius=0;
        private double middle_height=0;
        private double bottom_radius=0;
        private double bottom_height=0;
        Stool(){}
        Stool(double top_radius,double top_height,double middle_radius,double middle_height,double bottom_radius,double bottom_height){
            this.top_radius=top_radius;
            this.top_height=top_height;
            this.middle_radius=middle_radius;
            this.middle_height=middle_height;
            this.bottom_radius=bottom_radius;
            this.bottom_height=bottom_height;
        }
        public double getTop_radius() {
            return top_radius;
        }
        public void setTop_radius(double top_radius) {
            this.top_radius = top_radius;
        }
        public double getTop_height() {
            return top_height;
        }
        public void setTop_height(double top_height) {
            this.top_height = top_height;
        }
        public double getMiddle_radius() {
            return middle_radius;
        }
        public void setMiddle_radius(double middle_radius) {
            this.middle_radius = middle_radius;
        }
        public double getMiddle_height() {
            return middle_height;
        }
        public void setMiddle_height(double middle_height) {
            this.middle_height = middle_height;
        }
        public double getBottom_radius() {
            return bottom_radius;
        }
        public void setBottom_radius(double bottom_radius) {
            this.bottom_radius = bottom_radius;
        }
        public double getBottom_height() {
            return bottom_height;
        }
        public void setBottom_height(double bottom_height) {
            this.bottom_height = bottom_height;
        }
        public double getArea() {
            return (top_height*top_radius+middle_height*middle_radius+bottom_height*bottom_radius)*Math.PI*2+(top_radius*top_radius+bottom_radius*bottom_radius)*Math.PI*2-Double.parseDouble(AI);
        }
        public double getVolume() {
            return (top_radius*top_radius*top_height+middle_radius*middle_radius*middle_height+bottom_radius*bottom_radius*bottom_height)*Math.PI;
        }
    }
}