//说明继承的必要性
package com.test;public class test { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub //小学生对象 Pupil pl = new Pupil(); //中学生对象 MiddleStu ms = new MiddleStu(); //大学生对象 CollegeStu cs = new CollegeStu(); //设置fee pl.pay(100); ms.pay(500); cs.pay(1000); //打印设置的fee属性 System.out.println(pl.printFee()); System.out.println(ms.printFee()); System.out.println(cs.printFee()); }} //这里的方法不能为public类型 class Stu{ //定义成员属性 public int age; public String name; public float fee; public float printFee() { return fee; } } //小学生 class Pupil extends Stu{ //缴费 public void pay(float fee) { this.fee = fee; } } //中学生 class MiddleStu extends Stu{ //缴费 public void pay(float fee) { this.fee = fee*0.8f; } } //大学生 class CollegeStu extends Stu{ //缴费 public void pay(int fee) { this.fee = fee*0.1f; } }