多态初步认识

首先创建父类，因为BYD和BMW同输入汽车，有共同的属性和方法
 1 public class Car {
 2     int price;
 3     String type;
 4     String color;
 5     public Car() {
 6         super();
 7     }
 8     public Car(int price, String type, String color) {
 9         super();
10         this.price = price;
11         this.type = type;
12         this.color = color;
13     }
14     
15     public void show(){
16         System.out.println("I can run!");
17     }
18 }

创建BYD子类，并重写方法
 1 public class BYD extends Car {
 2     
 3     public BYD() {
 4         super();
 5     }
 6 
 7     public BYD(int price, String type, String color) {
 8         super(price, type, color);
 9     }
10 
11     public void show(){
12         System.out.println("BYD");
13         System.out.println("价格"+price);
14         System.out.println("型号"+type);
15         System.out.println("颜色"+color);
16     }
17 }

 1 public class BMW extends Car {
 2     
 3     public BMW() {
 4         super();
 5     }
 6 
 7     public BMW(int price, String type, String color) {
 8         super(price, type, color);
 9     }
10 
11     public void show(){
12         System.out.println("BMW");
13         System.out.println("价格"+price);
14         System.out.println("型号"+type);
15         System.out.println("颜色"+color);
16     }
17 }

静态和非静态的问题也要注意，到底是谁调用
 1 public class Driver {
 2     static String name;
 3     
 4     public Driver(String sex) {
 5         this.name = name;
 6     }
 7     public Driver() {
 8     }
 9     /*
10      * 创建方法
11      */
12     public static void drive(Car A){//static?
13         System.out.println(name+"Let's run!");
14         A.show();
15     }
16     
17     public static void main(String[] args) {
18         Driver driver=new Driver("张三");
19         Car byd=new BYD(3000000,"唐","红");
20         driver.drive(byd);//这样调用可以不是static
21         Car bmw=new BMW(8000000,"x5","黑");
22         Driver.drive(bmw);//这样调用必须是static
23     }
24 }