JAVA设计模式之工厂模式

<!--[if !supportLists]-->（2）??? <!--[endif]-->当一个产品族中的多个对象被设计成一起工作时，它能够保证客户端始终只使用同一个产品族中的对象。

缺点：

（1）添加新的产品对像时，难以扩展抽象工厂以便生产新种类的产品。

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（1）一个系统不应当依赖于产品类实例如何被创建、组合和表达的细节。这对于所有形态的工厂模式都是重要的；

（2）一个系统的产品有多于一个的产品族，而系统只消费其中某一族的产品；

（3）同属于同一个产品族的产品是在一起使用的，这一约束必须要在系统的设计中体现出来；

（4）系统提供一个产品类的库，所有的产品以同样的接口出现，从而使客户端不依赖于实现。

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例：

//抽象产品

UpperClothes.java

publicabstract class UpperClothes {

?????? public abstract int getChestSize();

?????? public abstract int getHeight();

?????? public abstract String getName();

}

Trousers.java

publicabstract class Trousers {

?????? public abstract int getWaistSize();

?????? public abstract int getHeight();

?????? public abstract String getName();

}

//具体产品

WesternUpperClothes.java

publicclass WesternUpperClothes extends UpperClothes {

?????? private int chestSize;

?????? private int height;

?????? private String name;

?????? WesternUpperClothes(String name,intchestSize,int height){

????????????? this.name=name;

????????????? this.chestSize=chestSize;

????????????? this.height=height;

?????? }

?????? public int getChestSize() {

????????????? return chestSize;

?????? }

?????? public int getHeight() {

????????????? return height;

?????? }

?????? public String getName() {

????????????? return name;

?????? }

}

CowboyUpperClothes.java

publicclass CowboyUpperClothes extends UpperClothes {

?????? private int chestSize;

?????? private int height;

?????? private String name;

?????? CowboyUpperClothes(String name,intchestSize,int height){

????????????? this.name=name;

????????????? this.chestSize=chestSize;

????????????? this.height=height;

?????? }

?????? public int getChestSize() {

????????????? return chestSize;

?????? }

?????? public int getHeight() {

????????????? return height;

?????? }

?????? public String getName () {

????????????? return name;

?????? }

}

WesternTrousers.java

publicclass WesternTrousers extends Trousers {

?????? private int waistSize;

?????? private int height;

?????? private String name;

?????? WesternTrousers(String name,intwaistSize,int height){

????????????? this.name=name;

????????????? this.waistSize=waistSize;

????????????? this.height=height;

?????? }

?????? public int getHeight() {

????????????? return height;

?????? }

?????? public String getName() {

????????????? return name;

?????? }

?????? public int getWaistSize() {

????????????? return waistSize;

?????? }

}

CowboyTrousers.java

publicclass CowboyTrousers extends Trousers {

?????? private int waistSize;

?????? private int height;

?????? private String name;

?????? CowboyTrousers(String name,intwaistSize,int height){

????????????? this.name=name;

????????????? this.waistSize=waistSize;

????????????? this.height=height;

?????? }

?????? public int getHeight() {

????????????? return height;

?????? }

?????? public String getName() {

????????????? return name;

?????? }

?????? public int getWaistSize() {

????????????? return waistSize;

?????? }

}

//抽象工厂

ClothesFactory.java

publicabstract class ClothesFactory {

?????? public abstract UpperClothescreateUpperClothes(int chestSize,int height);

?????? public abstract Trousers createTrousers(intwaistSize,int height);

}

//具体工厂

BeijingClothesFactory.java

publicclass BeijingClothesFactory extends ClothesFactory {

?????? public Trousers createTrousers(int waistSize,int height) {

????????????? return new WesternTrousers("北京牌裤子",waistSize,height);

?????? }

?????? public UpperClothescreateUpperClothes(int chestSize, int height) {

????????????? return newWesternUpperClothes("北京牌上衣",chestSize,height);

?????? }

}

ShanghaiClothesFactory.java

publicclass ShanghaiClothesFactory extends ClothesFactory {

?????? public Trousers createTrousers(int waistSize,int height) {

????????????? return new WesternTrousers("上海牌裤子",waistSize,height);

?????? }

?????? public UpperClothescreateUpperClothes(int chestSize, int height) {

????????????? return newWesternUpperClothes("上海牌上衣",chestSize,height);

?????? }

}

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