设计一个名为Fan的类来代表风扇。这个类包括三个常量SLOW,MEDIUM和FAST，其值分别为1,2,3,表示风扇的速度

/**
 *作者：魏宝航
 *2020年11月27日,下午10:41
 */
package 测试;
import java.util.*;
public class Test{
  public static void main(String[] args) {
    Fan fan1=new Fan();
    Fan fan2=new Fan();
    fan1.setSpeed(Fan.FAST);
    fan1.setRadius(10);
    fan1.setColor("yellow");
    fan1.setOn(true);
    fan2.setSpeed(Fan.MEDIUM);
    fan2.setRadius(5);
    fan2.setColor("blue");
    fan2.setOn(false);
    System.out.println(fan1.toString());
    System.out.println(fan2.toString());
  }
}
class Fan{
  static final int SLOW=1;
  static final int MEDIUM=2;
  static final int FAST=3;
  private int speed=SLOW;
  private boolean on=false;
  private double radius=5;
  private String color="blue";
  public Fan() {}
  public int getSpeed() {
    return speed;
  }
  public void setSpeed(int speed) {
    this.speed = speed;
  }
  public boolean isOn() {
    return on;
  }
  public void setOn(boolean on) {
    this.on = on;
  }
  public double getRadius() {
    return radius;
  }
  public void setRadius(double radius) {
    this.radius = radius;
  }
  public String getColor() {
    return color;
  }
  public void setColor(String color) {
    this.color = color;
  }
  @Override
  public String toString() {
    if(!on) {
      return "fan is off";
    }
    return "风扇的速度："+speed+"\n颜色："+color+"\n半径："+radius;
  }
}