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