java設(shè)計模式之工廠模式詳解

更新時間：2024年11月08日 09:30:48 作者：北極熊不在北極

本文介紹了三種常見的設(shè)計模式：簡單廠模式、工廠方法模式和抽象工廠模式,簡單廠模式通過一個工廠類來生產(chǎn)不同的產(chǎn)品實例,例如同時生產(chǎn)華為和小米手機,工廠方法模式則通過定義一個創(chuàng)建對象的接口,讓子類決定實例化哪一個類

一、簡單廠模式

一個工廠既代工生產(chǎn)華為手機也生產(chǎn)小米手機。

手機接口類

package com.liuyc.designpattern.factory;

public interface Phone {

    void showInfo();
}

華為手機實現(xiàn)類

package com.liuyc.designpattern.factory;

public class HuaWeiPhone implements Phone{
    @Override
    public void showInfo() {
        System.out.println("華為手機");
    }
}

小米手機實現(xiàn)類

package com.liuyc.designpattern.factory;

public class XiaoMiPhone implements Phone{
    @Override
    public void showInfo() {
        System.out.println("小米手機");
    }
}

生產(chǎn)手機工廠類

package com.liuyc.designpattern.factory.simplefactory;

import com.liuyc.designpattern.factory.Phone;

public class SimpleFactory {

    public static Phone getPhone(String className){
        Phone phone = null;
        try {
            Class<Phone> aClass = (Class<Phone>) Class.forName(className);
            phone = aClass.newInstance();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return phone;
    }
}

具體使用類

package com.liuyc.designpattern.factory.simplefactory;

import com.liuyc.designpattern.factory.Phone;

public class SimpleFactoryMain {

    public static void main(String[] args) {
        Phone phone = SimpleFactory.getPhone("com.liuyc.designpattern.factory.XiaoMiPhone");
        phone.showInfo();
    }
}

二、工廠方法模式

一個生產(chǎn)手機的工廠接口類

package com.liuyc.designpattern.factory.factorymethod;

import com.liuyc.designpattern.factory.Phone;

public interface PhoneFactory {

    Phone getPhone();
}

具體生產(chǎn)華為手機的工廠

package com.liuyc.designpattern.factory.factorymethod;

import com.liuyc.designpattern.factory.HuaWeiPhone;
import com.liuyc.designpattern.factory.Phone;

public class HuaWeiPhoneFactory implements PhoneFactory {
    @Override
    public Phone getPhone() {
        return new HuaWeiPhone();
    }
}

具體生產(chǎn)小米手機的工廠

package com.liuyc.designpattern.factory.factorymethod;

import com.liuyc.designpattern.factory.Phone;
import com.liuyc.designpattern.factory.XiaoMiPhone;

public class XiaoMiPhoneFactory implements PhoneFactory {
    @Override
    public Phone getPhone() {
        return new XiaoMiPhone();
    }
}

具體使用類

package com.liuyc.designpattern.factory.factorymethod;

import com.liuyc.designpattern.factory.Phone;

public class FactoryMethodMain {

    public static void main(String[] args) {
        PhoneFactory phoneFactory = new XiaoMiPhoneFactory();
        Phone phone = phoneFactory.getPhone();
        phone.showInfo();
    }
}

三、抽象工廠模式

現(xiàn)在，不管是華為也好，小米也好，他們已不滿足于只生產(chǎn)手機了，他們也開始造車了，現(xiàn)在有一個“組”的概念了，或者說族。

小車的接口類

package com.liuyc.designpattern.factory;

public interface Car {

    void showInfo();
}

華為汽車

package com.liuyc.designpattern.factory;

public class HuaWeiCar implements Car {
    @Override
    public void showInfo() {
        System.out.println("華為小汽車");
    }
}

小米汽車

package com.liuyc.designpattern.factory;

public class XiaoMiCar implements Car {
    @Override
    public void showInfo() {
        System.out.println("小米汽車");
    }
}

抽象工廠，定義既能生產(chǎn)手機，也是生產(chǎn)汽車

package com.liuyc.designpattern.factory.abstactfactory;

import com.liuyc.designpattern.factory.Car;
import com.liuyc.designpattern.factory.Phone;

public interface AbstractFactory {

    Phone getPhone();

    Car getCar();
}

華為工廠

package com.liuyc.designpattern.factory.abstactfactory;

import com.liuyc.designpattern.factory.Car;
import com.liuyc.designpattern.factory.HuaWeiCar;
import com.liuyc.designpattern.factory.HuaWeiPhone;
import com.liuyc.designpattern.factory.Phone;

public class HuaWeiFactory implements AbstractFactory{
    @Override
    public Phone getPhone() {
        return new HuaWeiPhone();
    }

    @Override
    public Car getCar() {
        return new HuaWeiCar();
    }
}

小米工廠

package com.liuyc.designpattern.factory.abstactfactory;

import com.liuyc.designpattern.factory.*;

public class XiaoMiFactory implements AbstractFactory{
    @Override
    public Phone getPhone() {
        return new XiaoMiPhone();
    }

    @Override
    public Car getCar() {
        return new XiaoMiCar();
    }
}

具體使用

package com.liuyc.designpattern.factory.abstactfactory;

import com.liuyc.designpattern.factory.Car;
import com.liuyc.designpattern.factory.Phone;

public class AbstractFactoryMain {

    public static void main(String[] args) {
        AbstractFactory abstractFactory = new XiaoMiFactory();
        Car car = abstractFactory.getCar();
        Phone phone = abstractFactory.getPhone();
        car.showInfo();
        phone.showInfo();
    }
}