一、是什么

1. 定义

　　工厂方法模式: 由子类决定要创建的具体类是哪一个

　　抽象工厂: 允许客户创建对象的家族，而无需指定他们的具体类

2. 理解

　　从定义中可以看出, 抽象工厂包含了工厂方法，区别是抽象工厂创建的是家族

3. 好处:

　　封装具体对象的创建，促进松耦合

4. 设计原则

　　依赖倒置原则--依赖抽象，不依赖具体类

二、示例

工厂方法

1. 工厂相关类

/** * 工厂 */public abstract class Factory {    public abstract Milk makeMilk();}/** * A 工厂 */public class FactoryA extends Factory {    @Override    public Milk makeMilk() {        return new MilkA();    }}/** * B 工厂 */public class FactoryB extends Factory {    @Override    public Milk makeMilk() {        return new MilkB();    }}

2. 牛奶类

/** * 产品抽象类 */public abstract class Milk {    public abstract void print();}/** * 产品A */public class MilkA extends Milk {    @Override    public void print() {        System.out.println("我是牛奶A");    }}/** * 产品B */public class MilkB extends Milk {    @Override    public void print() {        System.out.println("我是牛奶B");    }}

3. 测试

/** * 测试类 */public class Main {    public static void main(String[] args) {        Factory factoryA = new FactoryA();        Factory factoryB = new FactoryB();        Milk milkA = factoryA.makeMilk();        Milk milkB = factoryB.makeMilk();        milkA.print();        milkB.print();    }}

抽象工厂

1. 代码背景，分为南京和杭州两家工厂，他们各自生产自己的产品

2. 芝士

/** * 芝士 */public abstract class Cheese {    public String address = "";    public Cheese(String address) {        this.address = address;    }    public abstract void print();}/** * 南京生产的芝士 */public class NanJingCheese extends Cheese {    public NanJingCheese(String address) {        super(address);    }    @Override    public void print() {        System.out.println(address + "的芝士");    }}/** * 杭州芝士 */public class HangZhouCheese extends Cheese {    public HangZhouCheese(String address) {        super(address);    }    @Override    public void print() {        System.out.println(address + "的芝士");    }}

3. 牛奶

/** * 产品抽象类 */public abstract class Milk {    public String address = "";    public Milk(String address) {        this.address = address;    }    public abstract void print();}/** * 南京的牛奶 */public class NanJingMilk extends Milk {    public NanJingMilk(String address) {        super(address);    }    @Override    public void print() {        System.out.println(address + "的牛奶");    }}/** * 杭州牛奶 */public class HangZhouMilk extends Milk {    public HangZhouMilk(String address) {        super(address);    }    @Override    public void print() {        System.out.println(this.address + "的牛奶");    }}

3. 工厂：生产一组产品

/** * 抽象工厂类 */public abstract class Factory {    public abstract Milk makeMilk();    public abstract Cheese makeCheese();}/** * 南京工厂 */public class NanJingFactory extends Factory {    @Override    public Milk makeMilk() {        return new NanJingMilk("南京江宁");    }    @Override    public Cheese makeCheese() {        return new NanJingCheese("南京江宁");    }}/** * 杭州工厂 */public class HangZhouFactory extends Factory {    @Override    public Milk makeMilk() {        return new HangZhouMilk("杭州萧山");    }    @Override    public Cheese makeCheese() {        return new HangZhouCheese("杭州萧山");    }}

4. 测试

/** * 测试类 */public class Main {    public static void main(String[] args) {        Factory hangZhouFactory = new HangZhouFactory();        Cheese hangZhouCheese = hangZhouFactory.makeCheese();        Milk hangZhouMilk = hangZhouFactory.makeMilk();        hangZhouCheese.print();        hangZhouMilk.print();        Factory nanJingFactory = new NanJingFactory();        Cheese nanJingCheese = nanJingFactory.makeCheese();        Milk nanJingMilk = nanJingFactory.makeMilk();        nanJingCheese.print();        nanJingMilk.print();    }}