java：接口实例

interface Printer
{
public void read();
}

class CanPrinter implements Printer
{
public void read(){
System.out.println("Canread");
};
}

class HPPrinter implements Printer
{
public void read(){
System.out.println("HPread");
};
}

class Test
{
public static void main(String args[]){
int flag=0;
Printer p = null;
if(flag==0){
p = new HPPrinter();
}else{
p = new CanPrinter();
}

p.read();
}
}

class PrinterFactory
{
Printer getPrinter(int flag){        //定义类型为Printer
Printer p = null;
if(flag==0){
p = new HPPrinter();
}else if(flag==1){
p = new CanPrinter();
}
return p;    //返回对象
}
}

class Test
{
public static void main(String args[]){
int flag=0;
PrinterFactory f = new PrinterFactory();
Printer printer = f.getPrinter(flag);
printer.read();
}
}