多态

多态是 同一个行为 具有 多个不同表现形式

 

实现方式：

1、继承父类，重写实现方法

2、实现接口，重写实现方法

3、抽象类

 

继承方式：

public class Printer {
    public void print() {
        System.out.println("I am Father Printer");
    }
}

public class BlackPrinter extends Printer{
    @Override
    public void print() {
        System.out.println("I am Black Printer!!!");
    }
}

public class ColorfulPrinter extends Printer {
    @Override
    public void print() {
        System.out.println("I am Colorful Printer!!!");
    }
}

public class Consumer {

    public static void main(String[] args) {
        Printer p1 = new Printer();
        Printer p2 = new ColorfulPrinter();
        Printer p3 = new BlackPrinter();
        p1.print();
        p2.print();
        p3.print();
    }
}

/*-------------输出如下---------------*/
I am Father Printer
I am Colorful Printer!!!
I am Black Printer!!!

 

 

接口方式

public interface Vehicle {
    void run();
}

public class Bike implements Vehicle {
    @Override
    public void run() {
        System.out.println("Bike is Running ...");
    }
}

public class Car implements Vehicle {
    @Override
    public void run() {
        System.out.println("Car Running...");
    }
}

public class Consumer {

    public static void main(String[] args) {
        Vehicle v1 = new Car();
        Vehicle v2 = new Bike();

        v1.run();
        v2.run();
    }
}

/*---------------输出如下---------------*/
Car Running...
Bike is Running ...