一、不使用工厂

披萨项目：要方便披萨品种的扩展、要便于维护、要能运行时扩展

披萨族的设计：

抽象Pizza类，有四个方法：prepare（）、bake(),cut(),box()

实际的披萨：GreekPizza和CheesePizza

披萨工厂设计：if…else … if …else

1、抽象Pizza类

package com.java.jikexueyuan.pizzastore.pizza;public abstract class Pizza {	protected String name;		public abstract void prepare();		public void bake()	{		System.out.println(name+" baking;");	}	public void cut()	{		System.out.println(name+" cutting;");	}	public void box()	{		System.out.println(name+" boxing;");	}	public void setname(String name)	{		this.name=name;	}}

2、实际的披萨类

1）、CheesePizza

package com.java.jikexueyuan.pizzastore.pizza;public class CheesePizza extends Pizza {	@Override	public void prepare() {		// TODO Auto-generated method stub		super.setname("CheesePizza");				System.out.println(name+" preparing;");	}}

2）、GreekPizza

package com.java.jikexueyuan.pizzastore.pizza;public class GreekPizza extends Pizza {	@Override	public void prepare() {		// TODO Auto-generated method stub		super.setname("GreekPizza");				System.out.println(name+" preparing;");	}}

3、一般OrderPizza实现类

package com.java.jikexueyuan.pizzastore;public class OrderPizza {	public OrderPizza() {		Pizza pizza = null;		String ordertype;				do {			ordertype = gettype();   //控制台输入						if (ordertype.equals("cheese")) {				pizza = new CheesePizza();			} else if (ordertype.equals("greek")) {				pizza = new GreekPizza();			} else if (ordertype.equals("pepper")) {				pizza = new PepperPizza();			} else if (ordertype.equals("chinese")) {				pizza = new ChinesePizza();			} else {				break;			}			pizza.prepare();			pizza.bake();			pizza.cut();			pizza.box();		} while (true);	}}

简单工厂总结：如果要扩展新的pizza，就要将OrderPizza这个简单工厂停下来修改其中代码。

4、怎么改进呢？

将变化的地方抽取出来，使用简单工厂来封装，这样就不用停止orderPizza的运行，如下：

二、简单工厂（从主类提取实例化（变化）部分）

定义一个实例化披萨对象的类，封装创建对象的代码

1、SimplePizzaFactory类

public class SimplePizzaFactory {	public Pizza CreatePizza(String ordertype) {		Pizza pizza = null;		if (ordertype.equals("cheese")) {			pizza = new CheesePizza();		} else if (ordertype.equals("greek")) {			pizza = new GreekPizza();		} else if (ordertype.equals("pepper")) {			pizza = new PepperPizza();		}		return pizza;	}}

2、新的OrderPizza类

public class OrderPizza {	SimplePizzaFactory mSimplePizzaFactory;	public OrderPizza(SimplePizzaFactory mSimplePizzaFactory) {		setFactory(mSimplePizzaFactory);	}	public void setFactory(SimplePizzaFactory mSimplePizzaFactory) {		Pizza pizza = null;		String ordertype;		this.mSimplePizzaFactory = mSimplePizzaFactory;		do {			ordertype = gettype();			pizza = mSimplePizzaFactory.CreatePizza(ordertype);			if (pizza != null) {				pizza.prepare();				pizza.bake();				pizza.cut();				pizza.box();			}		} while (true);	}

三、工厂方法模式

将对象的实例化推迟到子类

困惑：披萨项目加盟店

解决：将披萨对象实例化功能抽象成抽象方法，在不同加盟店具体实现功能；

1、抽象的OrderPizza

package com.java.jikexueyuan.pizzastore.method;public abstract class OrderPizza {	public OrderPizza() {		Pizza pizza = null;		String ordertype;		do {			ordertype = gettype();			pizza = createPizza(ordertype);			pizza.prepare();			pizza.bake();			pizza.cut();			pizza.box();		} while (true);	}    // 方法抽象出来	abstract Pizza createPizza(String ordertype);}

2、实际的OrderPizza

1）、纽约的NYOrderPizza

package com.java.jikexueyuan.pizzastore.method;public class NYOrderPizza extends OrderPizza {	@Override	Pizza createPizza(String ordertype) {		Pizza pizza = null;		if (ordertype.equals("cheese")) {			pizza = new NYCheesePizza();		} else if (ordertype.equals("pepper")) {			pizza = new NYPepperPizza();		}		return pizza;	}}

2）、伦敦的LDOrderPizza

public class LDOrderPizza extends OrderPizza {	@Override	Pizza createPizza(String ordertype) {		Pizza pizza = null;		if (ordertype.equals("cheese")) {			pizza = new LDCheesePizza();		} else if (ordertype.equals("pepper")) {			pizza = new LDPepperPizza();		}		return pizza;	}}

四、抽象工厂模式

定义一个接口，用于创建相关或有依赖关系的对象族，而无需明确指定具体类。

1、抽象AbsFactory类

package com.java.jikexueyuan.pizzastore.absfactory;public interface AbsFactory {	public Pizza CreatePizza(String ordertype) ;}

2、具体实现类

1）、伦敦LDFactory

package com.java.jikexueyuan.pizzastore.absfactory;public class LDFactory implements AbsFactory {	@Override	public Pizza CreatePizza(String ordertype) {		Pizza pizza = null;		if (ordertype.equals("cheese")) {			pizza = new LDCheesePizza();		} else if (ordertype.equals("pepper")) {			pizza = new LDPepperPizza();		}		return pizza;	}}

2）纽约NYFactory

package com.java.jikexueyuan.pizzastore.absfactory;public class NYFactory implements AbsFactory {	@Override	public Pizza CreatePizza(String ordertype) {		Pizza pizza = null;		if (ordertype.equals("cheese")) {			pizza = new NYCheesePizza();		} else if (ordertype.equals("pepper")) {			pizza = new NYPepperPizza();		}		return pizza;	}}

3、OrderPizza类（AbsFactory的具体工厂传进来创建pizza对象）

package com.java.jikexueyuan.pizzastore.absfactory;public class OrderPizza {	AbsFactory mFactory;	public OrderPizza(AbsFactory mFactory) {		setFactory(mFactory);	}	public void setFactory(AbsFactory mFactory) {		Pizza pizza = null;		String ordertype;		this.mFactory = mFactory;		do {			ordertype = gettype();			pizza = mFactory.CreatePizza(ordertype);			if (pizza != null) {				pizza.prepare();				pizza.bake();				pizza.cut();				pizza.box();			}		} while (true);	}}