多态

多态:对象执行某个行为方法式表现出不同的形态。
多态分两种:静态多态(编译多态)通过方法重载来实现,动态多态(运行多态),通过重写来实现。

动态多态一般通过父类的引用,指向子类的实例来实现。实例调用的时候,调的是子类的方法。

练习:

public class Che {        //父类Che
    protected String cheming;
    private String leixing;
    private String dangwei;
    
    public Che(String cheming){        //重载  参数符合会运行
        this.cheming = cheming;
    }
    public Che(String cheming,String leixing,String dangwei){  //重载  参数符合会运行
        this.cheming = cheming;
        this.leixing = leixing;
        this.dangwei = dangwei;
        
    }
    public void shache(){
        System.out.println(cheming+"z");
    }
    public void jiasu(){
        System.out.println(cheming+"s");
    }
    public void qidong(){
        System.out.println(cheming+"h");
    }
}
public class Byd extends Che {       //子类继承Che
    public Byd(String cheming){
        super(cheming);
    }
    public Byd(String cheming,String leixing,String dangwei){
        super(cheming,leixing,leixing);        
    }
    public void shache(){
        System.out.println(cheming+"正在刹车"+"1");
    }
    public void jiasu(){
        System.out.println(cheming+"正在加速"+"1");
    }
    public void qidong(){
        System.out.println(cheming+"正在启动"+"1");
    }
    
}
public class Jipu extends Che {      //子类也是继承Che
    public Jipu(String cheming) {  
        super(cheming);
    }
    public Jipu(String cheming,String leixing,String dangwei){  
        super(cheming,leixing,dangwei);
    }
    
    public void qidong(){
        System.out.println(cheming+"正在启动"+"2");
    }
    
    public void jiasu(){
        System.out.println(cheming+"加速"+"2");
    }
    
    public void shache(){
        System.out.println(cheming+"正在刹车"+"2");
    }
}
public class Siji {               //定义一个类Siji方法来调用父类方法
    public void jiashi(Che c){   //引用父类Che实例化子类
        c.qidong();              
        c.jiasu();
        c.shache();    
    }
}
    public static void main(String[] args) {
        Che b = new Byd("比亚迪");    //实参
        Che j = new Jipu("吉普");    //实参
        Siji s = new Siji();

        s.jiashi(b);     //再用jiashi()方法调用Byd
s.jiashi(j); //再用jiashi()方法调用Jipu 实现运行多态(动态多态) } }

 

posted @ 2016-12-27 21:13  滥好人  阅读(190)  评论(0编辑  收藏  举报