Java設(shè)計模式之工廠模式案例詳解

更新時間：2022年02月15日 09:24:18 作者：溫故知新之java

工廠模式（Factory Pattern）是Java中最常用的設(shè)計模式之一。這種類型的設(shè)計模式屬于創(chuàng)建型模式，它提供了一種創(chuàng)建對象的最佳方式。本文將通過案例詳細(xì)講解一下工廠模式，需要的可以參考一下

分類

1.簡單工廠模式

2.工廠方法模式

3.抽象工廠模式

案例

需求

根據(jù)蛋糕的不同口味，分別創(chuàng)建蘋果味和香蕉味的蛋糕實例

方案一:簡單工廠模式

定義蛋糕父類

/**
 * 蛋糕
 * @author:liyajie
 * @createTime:2022/2/14 10:17
 * @version:1.0
 */
public class Cake {
}

定義蘋果味的蛋糕

/**
 * 蘋果蛋糕
 * @author:liyajie
 * @createTime:2022/2/14 10:17
 * @version:1.0
 */
public class AppleCake extends Cake{
    public AppleCake(){
        System.out.println("創(chuàng)建了蘋果蛋糕實例");
    }
}

定義香蕉味的蛋糕

/**
 * 香蕉蛋糕
 * @author:liyajie
 * @createTime:2022/2/14 10:17
 * @version:1.0
 */
public class BananaCake extends Cake{
    public BananaCake(){
        System.out.println("創(chuàng)建了香蕉蛋糕實例");
    }
}

定義蛋糕工廠類

/**
 * 蛋糕工廠
 * @author:liyajie
 * @createTime:2022/2/14 10:16
 * @version:1.0
 */
public class CakeFactory {

    public Cake createCake(String type){
        if("apple".equals(type)){
            return new AppleCake();
        }else if("banana".equals(type)){
            return new BananaCake();
        }else {
            return null;
        }
    }
}

定義測試類

/**
 * 測試類
 * @author:liyajie
 * @createTime:2022/2/14 10:25
 * @version:1.0
 */
public class Test {
    public static void main(String[] args) {
        CakeFactory cakeFactory = new CakeFactory();
        cakeFactory.createCake("apple");
        cakeFactory.createCake("banana");
    }
}

查看結(jié)果：

方案二:工廠方法模式

定義蛋糕父類

/**
 * 蛋糕父類
 * @author:liyajie
 * @createTime:2022/2/14 10:44
 * @version:1.0
 */
public abstract class Cake {

}

定義蘋果蛋糕

/**
 * 蘋果蛋糕
 * @author:liyajie
 * @createTime:2022/2/14 10:17
 * @version:1.0
 */
public class AppleCake extends Cake {
    public AppleCake(){
        System.out.println("創(chuàng)建了蘋果蛋糕實例");
    }
}

定義香蕉蛋糕

/**
 * 香蕉蛋糕
 * @author:liyajie
 * @createTime:2022/2/14 10:17
 * @version:1.0
 */
public class BananaCake extends Cake {
    public BananaCake(){
        System.out.println("創(chuàng)建了香蕉蛋糕實例");
    }
}

定義蛋糕工廠類該類主要是定義了createCake抽象方法，并且在無參構(gòu)造函數(shù)中進(jìn)行調(diào)用，具體的實現(xiàn)是在子類里進(jìn)行實例化的

/**
 * 蛋糕工廠類
 * @author:liyajie
 * @createTime:2022/2/14 11:55
 * @version:1.0
 */
public abstract class CakeFactory {

    abstract Cake createCake();

    public CakeFactory() {
        createCake();
    }
}

定義蘋果蛋糕工具類

/**
 * @desc:
 * @author:liyajie
 * @createTime:2022/2/14 11:58
 * @version:1.0
 */
public class AppleCakeFactory extends CakeFactory{

    @Override
    public Cake createCake() {
        return new AppleCake();
    }
}

定義香蕉蛋糕工具類

/**
 * @desc:
 * @author:liyajie
 * @createTime:2022/2/14 11:58
 * @version:1.0
 */
public class BananaCakeFactory extends CakeFactory{
    @Override
    public Cake createCake() {
        return new BananaCake();
    }
}

定義測試類

/**
 * 測試類
 * @author:liyajie
 * @createTime:2022/2/14 12:02
 * @version:1.0
 */
public class Test {
    public static void main(String[] args) {
        AppleCakeFactory appleCakeFactory = new AppleCakeFactory();

        BananaCakeFactory bananaCakeFactory = new BananaCakeFactory();
    }
}

查看結(jié)果

方案三:抽象工廠模式

定義蛋糕父類

/**
 * @desc:
 * @author:liyajie
 * @createTime:2022/2/14 10:44
 * @version:1.0
 */
public abstract class Cake {

}

定義蘋果蛋糕

/**
 * 蘋果蛋糕
 * @author:liyajie
 * @createTime:2022/2/14 10:17
 * @version:1.0
 */
public class AppleCake extends Cake {
    public AppleCake(){
        System.out.println("創(chuàng)建了蘋果蛋糕實例");
    }
}

定義香蕉蛋糕

/**
 * 香蕉蛋糕
 * @author:liyajie
 * @createTime:2022/2/14 10:17
 * @version:1.0
 */
public class BananaCake extends Cake {
    public BananaCake(){
        System.out.println("創(chuàng)建了香蕉蛋糕實例");
    }
}

定義蛋糕工廠類

/**
 * @desc:
 * @author:liyajie
 * @createTime:2022/2/14 11:55
 * @version:1.0
 */
public interface CakeFactory {

    Cake createCake();
}

定義蘋果蛋糕工廠類

/**
 * @desc:
 * @author:liyajie
 * @createTime:2022/2/14 11:58
 * @version:1.0
 */
public class AppleCakeFactory implements CakeFactory {

    @Override
    public Cake createCake() {
        return new AppleCake();
    }
}

定義香蕉蛋糕工廠類

/**
 * @desc:
 * @author:liyajie
 * @createTime:2022/2/14 11:58
 * @version:1.0
 */
public class BananaCakeFactory implements CakeFactory {
    @Override
    public Cake createCake() {
        return new BananaCake();
    }
}

定義蛋糕工廠生成器

/**
 * @desc:
 * @author:liyajie
 * @createTime:2022/2/14 17:46
 * @version:1.0
 */
public class FactoryProducter {

    CakeFactory cakeFactory;

    public FactoryProducter(CakeFactory cakeFactory){
        setCakeFactory(cakeFactory);
    }

    public void setCakeFactory(CakeFactory cakeFactory){
        this.cakeFactory = cakeFactory;
        cakeFactory.createCake();
    }
}

定義測試類

/**
 * 測試類
 * @author:liyajie
 * @createTime:2022/2/14 12:02
 * @version:1.0
 */
public class Test {
    public static void main(String[] args) {
        new FactoryProducter(new AppleCakeFactory());
        new FactoryProducter(new BananaCakeFactory());
    }
}

查看結(jié)果

對比分析

方案一：簡單工廠模式，工廠類是只有一個，只需要改動這一個地方避免了業(yè)務(wù)邏輯的代碼和創(chuàng)建對象的代碼大量耦合，降低耦合讓代碼更加條理清晰，更加優(yōu)雅
方案二：工廠方法模式是簡單工廠模式的衍生，定義一個創(chuàng)建對象的抽象方法，由子類決定要實例化的類，將對象實例化延遲到子類，實現(xiàn)了可擴(kuò)展，層次結(jié)構(gòu)更復(fù)雜，可以應(yīng)用到更復(fù)雜的場合
方案三：抽象工廠模式，定義一個接口來用于創(chuàng)建相關(guān)的或者具有依賴關(guān)系的對象簇，將實例化對象的細(xì)節(jié)提取出來，放到工廠角色，由工廠角色負(fù)責(zé)具體的創(chuàng)建細(xì)節(jié)，解耦合，提高項目可擴(kuò)展性和可維護(hù)性