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();
    }
}