工廠方法模式

工廠方法模式（Factory Method）,定義一個建立對象的接口，讓子類決定執行個體化哪一個類。工廠方法使一個類的實列化延遲到其子類。

 示意圖代碼如下：

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