java设计模式之工厂方法模式

工厂方法模式：定义了一个创建对象的接口，但由子类决定要实例化的类是哪一个。工厂方法让类把实例化推迟到子类。

烤鱼店之工厂模式类图： FactoryFish中的Fish实例化延迟到子类NianYuFactory，JiYuFactory中来实例化。这是工厂方法模式和简单工厂模式的区别。

Fish类代码实现：

public class Fish { String name = "Unknow name"; }

NianYu类代码实现：

public class NianYu extends Fish{ public NianYu() { // TODO Auto-generated constructor stub name = "鲶鱼"; System.out.println("一条烤"+name); } }

JiYu类代码实现：

public class JiYu extends Fish{ public JiYu() { // TODO Auto-generated constructor stub name = "鲫鱼"; System.out.println("一条烤"+name); } }

FactoryFish类代码实现：

public abstract class FactoryFish { public abstract Fish createFish(); }

NianYuFactory类代码实现：

public class NianYuFactory extends FactoryFish{ @Override public Fish createFish() { // TODO Auto-generated method stub return new NianYu(); } }

JiYuFactory类代码实现：

public class JiYuFactory extends FactoryFish{ @Override public Fish createFish() { // TODO Auto-generated method stub return new JiYu(); } }

KaoYu类代码实现：

public class KaoYu { FactoryFish factoryFish; public KaoYu(FactoryFish factoryFish){ this.factoryFish =factoryFish; } public void orderFish(){ factoryFish.createFish(); } }

FishTest类代码实现：

public class FishTest { public static void main(String[] args){ FactoryFish factoryFish = new JiYuFactory(); KaoYu kaoYu = new KaoYu(factoryFish); kaoYu.orderFish(); FactoryFish factoryFish2 = new NianYuFactory(); KaoYu kaoYu2 = new KaoYu(factoryFish2); kaoYu2.orderFish(); } }

运行结果：

一条烤鲫鱼 一条烤鲶鱼