我不知道怎么把数据带进去...

1. 这个是父类的abstract。

package com.imooc;

public abstract class Shape {

    public abstract void perimeter();    

    public abstract void area();

}

2. 然后是子类的Rectangle。尝试了一下失败了。

package com.imooc;

public class Rectangle extends Shape {

Rectangle p1 = new Rectangle();

private int periSum(){

int length = 10;

int width = 5;

int pSum = (length + width) *2;

return pSum;

}

@Override

public void perimeter() {

// TODO Auto-generated method stub

     System.out.println("圆形的周长是："+ p1.periSum());

}

@Override

public void area() {

// TODO Auto-generated method stub

     System.out.println("圆形的面积是：");

}

}

3. 接着是子类的Circle。

package com.imooc;

public class Circle extends Shape {

@Override

public void perimeter() {

// TODO Auto-generated method stub

       System.out.println("长方形的周长是：");

}

@Override

public void area() {

// TODO Auto-generated method stub

     System.out.println("长方形的面积是：");

}

}

4. 最后是Initial。

package com.imooc;

public class Initial {

public static void main(String[] args) {

// TODO Auto-generated method stub

    //计算周长

Shape per1 = new Rectangle();

    Shape per2 = new Circle();

    //求长方形的周长

    per1.perimeter();

    //求圆的周长

    per2.perimeter();

    //计算面积

    Shape ar1 = new Rectangle();

    Shape ar2 = new Circle();

    ar1.area();

    ar2.area();

}

}