1 package com.work;
2
3 public class father {
4
5 private String name;
6 private int age;
7 public String getName() {
8 return name;
9 }
10 public void setName(String name) {
11 this.name = name;
12 }
13 public int getAge() {
14 return age;
15 }
16 public void setAge(int age) {
17 this.age = age;
18 }
19
20 // public Father()
21 // {
22 // System.out.println("父类的构造方法");
23 // }
24 public father (String name)
25 {
26 System.out.println("父类的有参的构造方法");
27 this.name = name;
28 }
29 //工作
30 public void work()
31 {
32 System.out.println("我劳动我光荣");
33 }
34 }
1 package com.work;
2
3 public class Son extends father {
4 //Object a;所有类的父类
5
6 public Son()
7 {
8 //super 表示父类
9 super("儿子");
10 System.out.println("子类的构造方法");
11 }
12 public void sing()
13 {
14 System.out.println("我喜欢唱歌");
15 }
16 //覆盖（重写）
17 public void work()
18 {
19 //调用父类的方法
20 //super.work();
21 //System.out.println("我不喜欢上班，我要去参加海选");
22 System.out.println("我边上班边练歌");
23 }
24 public static Object getData(int i)
25 {
26 Object rtn = null;
27 //获取数据
28 if (i==1)
29 {
30 //1 father
31 father f = new father("向上转型的父类");
32 //向上转型
33 rtn = f;
34 }
35 else
36 {
37 //2 son
38 Son s = new Son();
39 rtn = s;
40 }
41 return rtn;
42 }
43 }
1 package com.work;
2
3 public class testjicheng {
4
5 public static void main(String[] args) {
6 //
7 father f = new father("父亲");
8
9 f.setName("父亲");
10
11 f.setAge(50);
12
13 System.out.println("名字是："+f.getName()+" 年龄是："+f.getAge());
14
15 f.work();
16
17 Son s = new Son();
18
19 s.setName("儿子");
20
21 s.setAge(20);
22
23 System.out.println("名字是："+s.getName()+" 年龄是："+s.getAge());
24
25 s.work();
26
27 s.sing();
28
29 System.out.println();
30
31 //转型
32
33 //向上转型 子类转成父类
34
35 father f1 = new Son();
36
37 System.out.println("名字是："+s.getName());
38
39 f1.work(); //如果被子类重写了，调用子类的方法
40
41 System.out.println("向下转型");
42
43 //向下转型 父类转成子类
44
45 //Son s1 = (Son) new Father("父亲");
46
47 Son s1 = (Son) f1;
48
49 s1.work();
50
51 System.out.println();
52
53 father f2 = (father)Son.getData(1);
54
55 f2.work();
56 }
57 }
