工厂方法设计模式：定义一个用于创建对象的接口，让子类来决定来创建具体的对象。在类的结构上，对象子类与工厂子类是平行关系的。
下面我们看一个简单的例子：
package net.itaem.create;
/**
* 接口：代表工厂要生产的对象
* */
public interface Fruit {
public void name();
public void price();
}
package net.itaem.create;
/**
* 具体的产品
* */
public class Apple implements Fruit{
@Override
public void name() {
System.out.println("the product name is apple");
}
@Override
public void price() {
System.out.println("the apple price is 10");
}
}
package net.itaem.create;
/**
* 具体的产品
* */
public class Banana implements Fruit {
@Override
public void name() {
System.out.println("the product is Banana");
}
@Override
public void price() {
System.out.println("the banana price is 10");
}
}
package net.itaem.create;
/**
* 定义一个工厂类，每个Concrete Factory负责生产具体的对象
* */
public abstract class FruitFactory {
public abstract Fruit create();
}
package net.itaem.create;
public class AppleFactory extends FruitFactory{
@Override
public Fruit create() {
return new Apple();
}
}
package net.itaem.create;
public class BananaFactory extends FruitFactory{
@Override
public Fruit create() {
return new Banana();
}
}
package net.itaem.create;
public class FactoryManager {
private FruitFactory factory;
/**
* 通过配置文件，读取具体的Factory对象
* */
public FactoryManager(FruitFactory factory){
this.factory = factory;
}
public void setFruitFactory(FruitFactory factory){
this.factory = factory;
}
public Fruit create(){
return factory.create();
}
public static void main(String[] args) {
System.out.println("-----------------------apple ---------------- ");
FactoryManager fruitFactory = new FactoryManager(new AppleFactory());
Fruit fruit = fruitFactory.create();
fruit.name();
fruit.price();
System.out.println("-----------------change to banana-------------------");
<span style="color:#ff0000;">fruitFactory.setFruitFactory(new BananaFactory());
fruit = fruitFactory.create();
fruit.name();
fruit.price();
}
}
-----------------------apple ---------------- the product name is apple the apple price is 10 -----------------change to banana------------------- the product is Banana the banana price is 10
类图结构：
总结：工厂方法是一种灵活的设计方式，该设计模式相对于静态工厂设计模式的最大优点就是，可以方便的扩展新的子类。
缺点：如果类过多，工厂对象的继承结构将会出现庞大的类。比如有1000种水果，那么就会有1000个工厂。
原文地址：http://blog.csdn.net/u010469003/article/details/26718521
