3.工厂方法模式(Factory Method)

介绍：工厂方法模式主要组成部分:抽象工厂类，实现抽象工厂类的具体工厂类、抽象类和实现抽象类的具体类.

说明:每一个产品都有要由一个具体的工厂来创建，把简单工厂拆分成一个个小工厂，每个小工厂只负责单独对象的创建，职责变小了，这样第个具体工厂就可以很好的控制各个对象的初始化了.

例:

package com.factorymethod;

public interface Animal {
	public void eat();

}


package com.factorymethod;

public class Bird implements Animal {

	public void eat() {
		System.out.println("小鸟会吃.");

	}
	
	public void fly(){
		System.out.println("小鸟会飞.");
	}

}



package com.factorymethod;

public class Dolphin implements Animal {

	public void eat() {
		System.out.println("海豚会吃.");

	}
	
	public void swim(){
		System.out.println("海豚会游泳.");
	}

}



package com.factorymethod;

public class Tiger implements Animal{
	
	public void run(){
		System.out.println("老虎会跑.");
	}

	public void eat() {
		System.out.println("老虎会吃.");
	}
	
	

}


package com.factorymethod;

/**
 * 
 * @Title: Factory.java
 * @Description: TODO(只负责定义创建方式的抽象工厂类)
 * @author [email protected] 
 * @date 2010-6-2 
 * @version V1.0
 */
public interface Factory {
	public Animal createAnimal();
}




package com.factorymethod;

/**
 * 
 * @Title: BirdFactory.java
 * @Description: TODO(具体工厂类)
 * @author [email protected] 
 * @date 2010-6-2
 * @version V1.0
 */
public class BirdFactory implements Factory{

	public Animal createAnimal() {
		return new Bird();
	}

}


package com.factorymethod;

public class DolphinFactory implements Factory{

	public Animal createAnimal() {
		return new Dolphin();
	}

}


package com.factorymethod;

public class TigerFactory implements Factory{

	public Animal createAnimal() {
		return new Tiger();
	}

}


package com.factorymethod;

/**
 * 
 * @Title: Client.java
 * @Description: TODO(客户类)
 * @author [email protected] 
 * @date 2010-6-2 
 * @version V1.0
 */
public class Client {
	
	public static void main(String[] args){
		Factory factory = new TigerFactory();
		Animal animal = factory.createAnimal();
		animal.eat();
		
		factory = new BirdFactory();
		animal = factory.createAnimal();
		animal.eat();
	}

}

UML: