Java之interface关键字

谁借莪１个温暖的怀抱￠ 2022-07-14 14:34 132阅读 0赞

接口是抽象方法和常量值的定义的集合

从本质上讲，接口是一种特殊的抽象类，这种抽象类中只包含常量和方法的定义，而没有变量和方法的实现

接口中的方法默认用abstract修饰

接口中的成员变量默认用public static finalt修饰

接口还可以继承其他的接口，并添加新的属性和方法

典型接口：

public interface Runner {
    	public static final int id = 1;
    	
    	public void start();
    	public void run();
    	public void stop();
    }

interface Singer {
    	public void sing();
    	public void sleep();
    	
    }
    interface Painter {
    	public void paint();
    	public void eat();
    }
    class Student implements Singer {
    	private String name;
    	Student(String name) {
    		this.name = name;
    	}
    	public void study() {
    		System.out.println("studying");
    		
    	}
    	public String getName() {
    		return name;
    	}
    	
    	public void sing() {
    		System.out.println("singing");
    	}
    	public void sleep() {
    		System.out.println("sleeping");
    	}
    }
    class Teacher implements Singer, Painter {
    	private String name;
    	Teacher(String name) {
    		this.name = name;
    	}
    	public void study() {
    		System.out.println("studying");
    		
    	}
    	public String getName() {
    		return name;
    	}
    	
    	public void sing() {
    		System.out.println("singing");
    	}
    	public void sleep() {
    		System.out.println("sleeping");
    	}
    		public void paint() {
    		System.out.println("painting");
    	}
    	public void eat() {
    		System.out.println("eating");
    	}
    }
    
    public class TestInterface {
    	public static void main(String[] args) {
    		Singer s1 = new Student("le");
    		s1.sing();
    		s1.sleep();
    		Singer s2 = new Teacher("steven");
    		s2.sing();
    		s2.sleep();
    		
    		Painter p1 = (Painter) s2;
    		p1.paint();
    		p1.eat();
    		
    	}
    }

**一个接口暴露一个对象的一部分方法！！！**