动态多态

public interface Ipower {
    public abstract void tigongdianyuan();
}

动态多态：指系统A访问系统B的服务时，系统B可以通过多种实现来提供服务，而这一切对于A来说都是透明的

public class ACPower implements Ipower {

    public void tigongdianyuan() {
        System.out.println("适配器提供电源");

    }

}

public class Barry implements Ipower {

    public void tigongdianyuan() {
        System.out.println("电池提供电源");

    }

}

public class Computer {

    public void kaiJi(Ipower pow){
        pow.tigongdianyuan();
        System.out.println("开机了");
    }

}

public class Test {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Computer c = new Computer();
        ACPower ac = new ACPower();
        Barry ba = new Barry();
        c.kaiJi(ba);
    }

}