mars老师java4android接口实例

1.创建一个Printer接口

interface Printer{

    public void open();

    public void print(String s);

    public void close();

}

2.创建一个PrinterFactory类

public class PrinterFactory{

    public static Printer getPrinter(int flag){

        Printer printer = null;

        

        if(flag == 0){

            printer = new HPPrinter();

        }else if(flag == 1){

            printer = new CanonPrinter();

        }else if(flag == 2){

            printer = new XXXPrinter();

        }

        return printer;

    }

}

3.创建HPPrinter类

class HPPrinter implements Printer{

    public void open(){

        System.out.println("HPPrinter open");

    }

    

    public void print(String s){

        System.out.println("HPPrinter print--->" + s);

    }

    

    public void close(){

        System.out.println("HPPrinter close");

    }

}

4.创建CanonPrinter类

class CanonPrinter implements Printer{

    private void clean(){

        System.out.println("CanonPrinter clean");

    }

    

    public void close(){

        this.clean();

        System.out.println("CanonPrinter close");

    }

    

    public void open(){

        System.out.println("CanonPrinter open");

    }

    

    public void print(String s){

        System.out.println("CanonPrinter print--->" + s);

    }

}

5.创建XXXPrinter类

public class XXXPrinter implements Printer{

    public void open(){

        System.out.println("XXXPrinter open");

    }

    

    public void print(String s){

        System.out.println("XXXPrinter print--->" + s);

    }

    

    public void close(){

        System.out.println("XXXPrinter close");

    }

}

6.创建Test类

public class Test{

    public static void main(String args[]){

        int flag = 2;

        

        Printer printer = PrinterFactory.getPrinter(flag);

        

        printer.open();

        printer.print("test");

        printer.close();

    }

}