利用反射实现简单工厂类，可以任意增加子类

//简单工厂设计模式
interface Vehicle        //写一个接口，但是我更喜欢叫它标准，所有符合这个标准的类均归为同一类
{
public void howToWork();
}
class Car implements Vehicle      //汽车类实现交通工具接口（或者说是汽车类符合交通工具标准）
{
public void howToWork()
{
System.out.println("开车去!");
}
}
class Bike implements Vehicle
{
public void howToWork()
{
System.out.println("骑车去!");
}
}
class Airplane implements Vehicle
{
public void howToWork()
{
System.out.println("坐飞机去!");
}
}
class Factory             //工厂类
{
public static Vehicle create(String vehicle)  //实现一个静态方法用于创建实例
{
Vehicle sample = null;
switch(vehicle)
{
case "car":
sample = new Car();
break;</span><span style="font-size:18px;">
case "bike":
sample = new Bike();
break;
case "airplane" :
sample = new Airplane();
break;
}
return sample;
}
}
public class SimpleFactory
{
public static void main(String args[])
{
Vehicle vehicle = Factory.create(args[0]);
vehicle.howToWork();
}
}</span>

package reflect;

//工厂设计模式升级版，简单工厂也可以解决之前难以维护的问题
interface Fruit // 定义接口
{
public void eat();
}

class Apple implements Fruit
{
@Override
public void eat()
{
// TODO Auto-generated method stub
System.out.println("eat Apple");
}
}

class Banana implements Fruit
{
@Override
public void eat()
{
// TODO Auto-generated method stub
System.out.println("eat Banana");
}
}
class Orange implements Fruit
{
@Override
public void eat()
{
// TODO Auto-generated method stub
System.out.println("eat Orange");
}
}
class Factory
{
public static Fruit getInstance(String className) throws Exception
{
Fruit f = null;
f = (Fruit) Class.forName(className).newInstance();  //利用反射实现实例化Fruit的子类
return f;
}
}

public class TestFactory
{
public static void main(String[] args) throws Exception
{
// TODO Auto-generated method stub
Fruit f = Factory.getInstance("reflect.Orange");
f.eat();
}

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