Java 中的向上转型 Father f = new Son();

 1 class Father{
 2     
 3     int i = 100;
 4     static int j = 101;
 5     final int m = 102;
 6     
 7     public void drive() {
 8         System.out.println("I can drive!");
 9     }
10     
11     public static void work() {
12         System.out.println("I can work!");
13     }
14     public Father() {
15         System.out.println("我是爸爸！");
16     }
17     18         19 20 21 }
22 
23 class Son extends Father {
24     int i = 10;
25     static int j = 11;
26     final int m = 12;
27     public Son() {
28         System.out.println("我是儿子！");
29     }
30     public void drive() {
31         System.out.println("I can not drive!");
32     }
33     
34     public void study() {
35         System.out.println("I should study!");
36     }
37     public static void work() {
38         System.out.println("I can not work!");
39     }
40 }
41 
42 public class TestNew {
43     public static void main(String[] args) {
44         
45         Father man = new Son(); 
46         System.out.println(man.i);
47         System.out.println(man.m);
48         System.out.println(man.j);
49         
50         man.drive();
51         Father.work();
52         //        man.study();报错！！！！
53     }
54     
55     /** Console:
56      * 100
57      * 102  
58      * 101
59      * I can not drive!
60      * I can work!
61      *
62      * 总结：
63      * 1、构造方法：子类和父类参数一致，先父后子
64      * 2、方法：向上转型时，静态方法用父类。子类特有无法调用，重写方法用子类
65      * 3、成员变量：都采用父类的
66      *
67      */
68 
69 }