1 abstract class A{    // 是定义了一个抽象类
 2     public static final String FLAG = "CHINA" ;    // 全局常量
 3 private String name = "张三" ; // 定义一个普通的属性  4  public void setName(String name){  5 this.name = name ;  6  }  7  public String getName(){  8 return this.name ;  9  } 10 public abstract void print() ; // 定义抽象方法 11  //构造方法 12  public A(){ 13 14  } 15 };

 1 package com.hhb.q;
 2 abstract class Person{
 3     private String name ;        // 定义name属性
 4     private int age ;            // 定义age属性
 5     public Person(String name,int age){
 6         this.name = name ;
 7         this.age = age ;
 8     }
 9     public void setName(String name){
10         this.name = name ;
11     }
12     public void setAge(int age){
13         this.age = age ;
14     }
15     public String getName(){
16         return this.name ;
17     }
18     public int getAge(){
19         return this.age ;
20     }
21     public abstract String getInfo() ;    // 抽象方法
22 };
23 class Student extends Person{
24     private String school ;
25     public Student(String name,int age,String school){
26         super(name,age) ;    // 指定要调用抽象类中有两个参数的构造方法
27         this.school = school ;
28     }
29     public void setSchool(String school){
30         this.school = school ;
31     }
32     public String getSchool(){
33         return this.school ;
34     }
35     public String getInfo(){
36         return    "姓名：" + super.getName()  +
37                 "；年龄：" + super.getAge() +
38                 "；学校：" + this.getSchool() ;
39     }
40 };
41 public class AbstractDemo04{
42     public static void main(String args[]){
43         Student stu = new Student("张三",30,"清华大学") ;
44         System.out.println(stu.getInfo()) ;
45     }
46 };