接口使用方法java

interface Person {
    public void fun1();
}

class Student implements Person {
    public void fun1() {
        System.out.println("Studnt Class fun1()");
    }
    public void fun2(){
    	System.out.println("Student Class fun2()");
    }
}

public class InterfaceApplianceDemo {
	
	public static void hehe(Person p){
        p.fun1();
        //利用接口實例化對象，對象p只能調用在接口中實現的實例化函數。。如p.fun2();會報錯
//      p.fun2();
        
        //可以將p強制轉換爲p2對象，使得可以用p2調用fun2()函數
        Student p2 = (Student)p;
        p2.fun2();
	}

<span style="white-space:pre">	</span>/*
<span style="white-space:pre">	</span> * 說明接口和它的實現類可以相互轉化
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>public static void haha(Student s){
<span style="white-space:pre">		</span>Person p = (Student)s;
<span style="white-space:pre">		</span>
<span style="white-space:pre">		</span>p.fun1();
<span style="white-space:pre">		</span>//不可以
//<span style="white-space:pre">		</span>p.fun2();
<span style="white-space:pre">	</span>}
    public static void main(String[] args) {
        Person p = new Student();//接口對象實例化，對象的多態性
        p.fun1();
        //利用接口實例化對象，對象p只能調用在接口中實現的實例化函數。。如p.fun2();會報錯
//      p.fun2();
        
        //可以將p強制轉換爲p2對象，使得可以用p2調用fun2()函數
        Student p2 = (Student)p;
        p2.fun2();
    }
}