JAVA学习--面向对象的特征二：继承性

  1 public class TestExtends {
  2     public static void main(String[] args) {
  3         Student s = new Student();
  4         s.eat();
  5        
  6         Worker w = new Worker();
  7         w.eat();
  8        
  9         Person p = new Person();
 10         p.eat();
 11        
 12         s.setAge(12);
 13         s.setName("麻华龙");
 14         System.out.println(s.getName() + ":" + s.getAge());
 15        
 16         Graduate g = new Graduate();
 17         g.eat();
 18         g.info();
 19         g.show();
 20     }
 21 }
 22 
 23 class Person {
 24     private String name;
 25     private int age;
 26 
 27     public String getName() {
 28         return name;
 29     }
 30 
 31     public void setName(String name) {
 32         this.name = name;
 33     }
 34 
 35     public int getAge() {
 36         return age;
 37     }
 38 
 39     public void setAge(int age) {
 40         this.age = age;
 41     }
 42 
 43     public void eat() {
 44         System.out.println("吃饭");
 45     }
 46 
 47     void walk() {
 48         System.out.println("走路");
 49     }
 50     private void sleep(){
 51        
 52     }
 53 }
 54 
 55 class A{
 56    
 57 }
 58 
 59 class Student extends Person{
 60 // class Student extends Person,A{
 61 //    private String name;
 62 //    private int age;
 63     private String schoolName;
 64    
 65     public Student(){
 66        
 67     }
 68     public Student(String name,int age){
 69 //        this.name = name;
 70 //        this.age = age;
 71         this.setName(name);
 72         this.setAge(age);
 73     }
 74    
 75 //    public String getName() {
 76 //        return name;
 77 //    }
 78 //    public void setName(String name) {
 79 //        this.name = name;
 80 //    }
 81 //    public int getAge() {
 82 //        return age;
 83 //    }
 84 //    public void setAge(int age) {
 85 //        this.age = age;
 86 //    }
 87 //   
 88 //    对父类同名的方法的重写、覆盖
 89     public void eat(){
 90         System.out.println("应该多吃有营养的");
 91     }
 92     public void walk(){
 93         System.out.println("背着书包蹦蹦跳跳的走路");
 94     }
 95     public void info(){
 96         eat();
 97         //System.out.println("name:" + name);
 98         System.out.println("我是一个学生");
 99     }
100     //不是对父类私有的sleep()方法的重写。
101     private int sleep(){
102         return 0;
103     }
104    
105 }
106 
107 
108 
109 class Worker extends Person{
110     public void eat(){
111         System.out.println("工人吃饭");
112     }
113      
114      public void walk(){
115          
116      }
117 }
118 
119 class Graduate extends Student{
120     public void show(){
121         System.out.println("我是一个研究生");
122     }
123 }