java通过反射机制实现工厂设计模式

package org.lxh.demo15.factorydemo01 ;
interface Fruit{
public void eat() ;	// 吃水果
}
class Apple implements Fruit{
public void eat(){			// 覆写eat()方法
System.out.println("** 吃苹果");
}
};
class Orange implements Fruit{
public void eat(){
System.out.println("** 吃橘子") ;
}
};
class Factory{
public static Fruit getInstance(String className){
Fruit fruit = null ;
try{
fruit = (Fruit)Class.forName(className).newInstance() ;
}catch(Exception e){
e.printStackTrace() ;
}
return fruit ;
}
};
public class FactoryDemo01{
public static void main(String args[]){
Fruit f = Factory.getInstance("org.lxh.demo15.factorydemo01.Apple") ;
if(f!=null){
f.eat() ;
}
}
};

package org.lxh.demo15.factorydemo02 ;
import java.util.Properties ;
import java.io.File ;
import java.io.FileOutputStream ;
import java.io.FileInputStream ;
interface Fruit{
public void eat() ;	// 吃水果
}
class Apple implements Fruit{
public void eat(){			// 覆写eat()方法
System.out.println("** 吃苹果");
}
};
class Orange implements Fruit{
public void eat(){
System.out.println("** 吃橘子") ;
}
};
class Init{
public static Properties getPro(){
Properties pro = new Properties() ;
File f = new File("d:\\fruit.properties") ;	// 找到属性文件
try{
if(f.exists()){	// 文件存在
pro.load(new FileInputStream(f)) ;	// 读取属性
}else{
pro.setProperty("apple","org.lxh.demo15.factorydemo02.Apple") ;
pro.setProperty("orange","org.lxh.demo15.factorydemo02.Orange") ;
pro.store(new FileOutputStream(f),"FRUIT CLASS") ;
}
}catch(Exception e){}
return pro ;
}
};
class Factory{
public static Fruit getInstance(String className){
Fruit fruit = null ;
try{
fruit = (Fruit)Class.forName(className).newInstance() ;
}catch(Exception e){
e.printStackTrace() ;
}
return fruit ;
}
};
public class FactoryDemo02{
public static void main(String args[]){
Properties pro = Init.getPro() ;
Fruit f = Factory.getInstance(pro.getProperty("apple")) ;
if(f!=null){
f.eat() ;
}
}
};