精通Java接口的使用与原理

[修饰符] interface 接口名 extends 父接口1，父接口2，…{
//常量定义
//方法定义
}
class 类名 extends 父类名 implements 接口1，接口2，…{
//类成员
}

//先定义USB接口，通过service()方法提供服务

public interface UsbInterFace {
	
	void service();
}

//定义U盘类，实现USB接口中的service()方法，进行数据传输

public class UDisk implements UsbInterFace{
	public void service(){
		System.out.println("连接USB口，开始传输数据");
	}

}

//定义USB风扇类，实现USB接口中的service()方法，获得电流使风扇转动

public class UsbFan implements UsbInterFace{
	public void service(){
		System.out.println("连接USB口,获得电流，风扇开始转动");
	}
}
//编写测试类，实现U盘传输数据，使USB风扇转动

public class Test {

	public static void main(String[] args) {
		//1.U盘
		UsbInterFace uDisk=new UDisk();
		uDisk.service();
		//2.USB风扇
		UsbInterFace usbFan=new UsbFan();
		usbFan.service();
	}
}

//定义Door类，具有开和关的功能

public abstract class Door {
	public abstract void open();//开
	public abstract void close();//关
}

//定义Lock接口，具备上锁和开锁的功能

public interface Lock {
	void lockUp();//上锁
	void openLock();//开锁
}

//定义TheftproofDoor类，继承Door类，实现Lock接口
*
 * 防盗门类
 */
public class TheftproofDoor extends Door implements Lock,DoorBell{
	public void lockUp() {
		System.out.println("插进钥匙，向左旋转钥匙三圈，锁上了，拔出钥匙");
	}
	public void openLock(){
		System.out.println("插进钥匙，向右旋转钥匙三圈，锁打开了，拔出钥匙");
	}
	public void open(){
		System.out.println("用力推，门打开了");
	}
	public void close(){
		System.out.println("轻轻拉门，门关上了");
	}
}

//编写测试类，实现防盗门的关门，开门，上锁，开锁的功能

public class DoorTest {
	public static void main(String[] args) {
		TheftproofDoor tfd=new TheftproofDoor();
		tfd.close();//关门
		tfd.lockUp();//上锁
		tfd.takePictures();//来访客人拍照存储
		tfd.openLock();//开锁
		tfd.open();//开门
	}
}

public interface DoorBell {
	void takePictures();//铃响拍照存档功能
}

//为防盗门增加门铃功能

public class TheftproofDoor extends Door implements Lock,DoorBell{
//省略其他实现方法
public void takePictures(){
		System.out.println("铃......咔嚓......照片已存储");
	}
}

//修改测试类，代码如下：

public class DoorTest {
	public static void main(String[] args) {
		TheftproofDoor tfd=new TheftproofDoor();
		tfd.close();//关门
		tfd.lockUp();//上锁
		tfd.takePictures();//来访客人拍照存储
		tfd.openLock();//开锁
		tfd.open();//开门
	}
}

//定义墨盒接口InkBox，约定墨盒有颜色

public interface InkBox {
	
	public String getColor();
}

//定义纸张接口Paper，约定纸张有大小

public interface Paper {
	
	public String getSize();
}

//定义打印机类，引用墨盒接口，纸张接口实现打印功能

public class Printer {
	InkBox inkBox;//墨盒
	Paper paper;//纸张
	
	public void setInkBox(InkBox inkBox){
		this.inkBox=inkBox;
	}
	
	public void setPaper(Paper paper){
		this.paper=paper;
	}
	
	public void print(){
		System.out.println("使用"+inkBox.getColor()+"墨盒在"+paper.getSize()+"纸张上打印");
	}
}

//墨盒厂商按照InkBox接口实现ColorInkbox类和GrayInkBox类

public class ColorInkBox implements InkBox{
	public String getColor(){
		return "彩色";
	}
}


public class GrayInkBox implements InkBox{
	public String getColor(){
		return "黑色";
	}
}


public class GrayInkBox implements InkBox{
	public String getColor(){
		return "黑色";
	}
}


public class GrayInkBox implements InkBox{
	public String getColor(){
		return "黑色";
	}
}
//纸张厂商按照Paper接口实现A4Paper类和B5Paper类
public class A4Paper implements Paper{
	public String getSize(){
		return "A4";
	}
}
public class B5Paper implements Paper{
	public String getSize(){
		return "B5";
	}

}
//“组装”打印机，让打印机通过不同的墨盒和纸张实现打印
public class TestInkBox {
	public static void main(String[] args) {
		//1.定义打印机
		InkBox inkBox=null;
		Paper paper=null;
		Printer printer=new Printer();
		
		//2.使用黑白墨盒在A4纸上打印
		inkBox=new GrayInkBox();
		paper=new A4Paper();
		printer.setInkBox(inkBox);
		printer.setPaper(paper);
		printer.print();
		
		3.使用彩色墨盒在B5纸上打印
		inkBox=new ColorInkBox();
		paper=new B5Paper();
		printer.setInkBox(inkBox);
		printer.setPaper(paper);
		printer.print();
		
		//4.使用彩色墨盒在A4纸上打印
		paper=new A4Paper();
		printer.setPaper(paper);
		printer.print();
	}
}

[修饰符] interface 接口名：父接口1，父接口2，…{
属性定义
方法定义
}
class 类名：父类名，接口1，接口2，…{}

namespace InterfaceDemo
{
    public interface InkBox
    {
        string Color { get; }
    }
    public interface Paper
    {
        string Size { get; }
    }
    class Printer
    {
        InkBox inkBox;//墨盒
        public InkBox InkBox
        {
            set { inkBox = value; }
        }
        Paper paper;//纸张
        public Paper Paper
        {
            set { paper = value; }
        }
        public void print()
        {
            Console.WriteLine("使用" + inkBox.Color + "墨盒在" + paper.Size + "纸上打印");
        }
    }
    public class ColorInkBox: InkBox
    {
        public string Color { get { return "彩色"; } }
    }
    public class GrayInkBox: InkBox
    {
        public string Color { get { return "黑白"; } }
    }
    public class A4Paper : Paper
    {
        public string Size { get { return "A4"; } }
    }
    public class B5Paper : Paper
    {
        public string Size { get { return "B5"; } }
    }
    public class Program
    {
        static void Main(string[] args)
        {
            InkBox inkBox = null;
            Paper paper = null;
            Printer printer = new Printer();

            inkBox = new GrayInkBox();
            paper = new A4Paper();
            printer.InkBox = inkBox;
            printer.Paper = paper;
            printer.print();

            inkBox = new ColorInkBox();
            paper = new B5Paper();
            printer.InkBox = inkBox;
            printer.Paper = paper;
            printer.print();

            paper = new A4Paper();
            printer.Paper = paper;
            printer.print();
            Console.ReadLine();
        }
    }
}