public class Test {

     public static void main(String[] args){

         try{

             Factory.factory("A").doSth();

             Factory.factory("B").doSth();

             Factory.factory("C").doSth();

         }catch(BadProductException e){

             e.printStackTrace();

         }

     }

 }

 class Factory{

     public static Product factory(String product) throws BadProductException{

         if(product.equals("A"))

             return new ConcreteProductA();

         else if(product.equals("B"))

             return new ConcreteProductB();

         else

             throw new BadProductException("产品标识有误！");

     }

 }

 interface Product{

     void doSth();

 }

 class ConcreteProductA implements Product{

     @Override

     public void doSth() {

         System.out.println("ConcreteProductA.doSth()");

     }

 }

 class ConcreteProductB implements Product{

     @Override

     public void doSth() {

         System.out.println("ConcreteProductB.doSth()");

     }

 }

 class BadProductException extends Exception{

     public BadProductException(String msg){

         super(msg);

     }

 }