封装、继承、多态

package com.duotai;

public class Main {

    public static void main(String[] args) {
        new RoundGlyph2(21);
    }
}
class Glyph{

    public Glyph(){
        System.out.println("Glyph.draw() before");
        draw();
        System.out.println("Glyph.draw() after");
    }

    public void draw(){
        System.out.println("Glyph.draw()");
    }
}
class RoundGlyph extends Glyph{

    public int radius=9;

    public RoundGlyph(){

    }

    public RoundGlyph(int radius){
        System.out.println("RoundGlyph构造器，radius="+radius);
    }

    public void draw(){
        System.out.println("RoundGlyph.draw()，radius="+radius);
    }
}
class RoundGlyph2 extends RoundGlyph{

    public RoundGlyph2(int radius) {
        System.out.println("RoundGlyph2构造器，radius="+radius);
    }

//    public void draw(){
//        System.out.println("RoundGlyph2.draw()，radius="+radius);
//    }
}

Glyph.draw() before
RoundGlyph.draw()，radius=0
Glyph.draw() after
RoundGlyph2构造器，radius=21

Glyph.draw() before
RoundGlyph2.draw()，radius=0
Glyph.draw() after
RoundGlyph2构造器，radius=21