设计摘自久久学院
看了论坛上的文章，读FactoryMethod Pattern UML图，写了个小例子程序。做为文章的补充！
//Creator.java

public abstract class Creator
{
/**
* looks like a factory
* contains some products and some process methods
*/
protected Product duct;
abstract String processProduct();
abstract String processProductSpecial();
public String Operation()
{
return processProduct(); // FactoryMethod for implemention;
}
}

//ConcreteProduct.java

public class ConcreteProduct extends Product
{
public ConcreteProduct()
{
System.out.println("construct the ConcreteProduct object");
}
public String makeString(String str)
{
return "This is the product after processing:"+str;
}
}

//Product.java
public abstract class Product
{
public abstract String makeString(String str);
}

//ConcreteCreatorA.java

public class ConcreteCreatorA extends Creator
{
/**
* You can write some other class like this to override
* the same methods do diffrent thing;
*/
public ConcreteCreatorA()
{
duct=new ConcreteProduct();
System.out.println("instanced a product");

}
public String processProduct()
{
System.out.println("product A:");
return duct.makeString("Make #a product");

}
public String processProductSpecial()
{
System.out.println("special product B:");
//add another method here
return duct.makeString("Make Special #B product");
}
}



//TestFactoryMethod.java
public class TestFactoryMethod
{
public TestFactoryMethod()
{
}
public static void main(String[] arg)
{
ConcreteCreatorA cc=new ConcreteCreatorA();
System.out.println(cc.Operation());
System.out.println(cc.processProductSpecial());
}
}