工厂方法模式

工厂方法模式（Factory Method）,定义一个创建对象的接口，让子类决定实例化哪一个类。工厂方法使一个类的实列化延迟到其子类。

示意图代码如下：

1 public abstract class Product {
2     public abstract void show();
3 }

Product

1 public class ConcreteProduct extends Product {
2 
3     @Override
4     public void show() {
5         System.out.println("ConcreteProduct...show....");
6         
7     }
8 
9 }

ConcreteProduct

1 public abstract class Creator {
2     public abstract Product factoryMethod();
3 }

Creator

1 public class ConcreteCreator extends Creator {
2 
3     @Override
4     public ConcreteProduct factoryMethod() {
5         return new ConcreteProduct();
6 
7     }
8 
9 }

ConcreteCreator

1 public class TestFactory {
2     public static void main(String[] args) {
3         Creator c = new ConcreteCreator();
4         ConcreteProduct pro = (ConcreteProduct) c.factoryMethod();
5         pro.show();
6     }
7 }

test