Java设计模式之简单工厂模式

• • 简单工厂模式

    使用参数或者配置文件等事先定义好的变量，然后利用分支判断初始化具体产品类并返回；
    不符合“开发-封闭”原则，每次增加产品，都需要修改类方法。工厂类单一，不用维护大量的工厂类；
    工厂方法模式和抽象工厂模式规避了不符合“开发-封闭”原则，同时支持更灵活的增加产品；

  • 适用性

    1）当一个类不知道它所必须创建的对象的类的时候。
    2）当一个类希望由它的子类来指定它所创建的对象的时候。

  • 举例

    如哈佛汽车加工厂既可以生产跑车又可以生产卡车。

  • UML类图
    

  • 代码示例

    • 定义哈佛汽车接口（或抽象类）

      package com.jin.demo.DesignPatterns.Factory.SimpleFactory;
      
      /**
       * 定义哈佛汽车接口（或抽象类）
       * @auther jinsx
       * @date 2019-05-15 08:58
       */
      public interface HFCar {
      	// 什么汽车都可以跑
      	void run();
      }
      

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    • 哈佛跑车

      package com.jin.demo.DesignPatterns.Factory.SimpleFactory;
      
      /**
       * 哈佛跑车
       * @auther jinsx
       * @date 2019-05-15 09:00
       */
      public class HFRoadster implements HFCar{
      	@Override
      	public void run() {
      		System.out.println("哈佛小跑车，起步就是快");
      	}
      }
      

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    • 哈佛卡车

      package com.jin.demo.DesignPatterns.Factory.SimpleFactory;
      
      /**
       * 哈佛卡车
       * @auther jinsx
       * @date 2019-05-15 09:03
       */
      public class HFTruck implements HFCar {
      	@Override
      	public void run() {
      		System.out.println("哈佛小卡车，运输能力就是强");
      	}
      }
      

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    • 声明简单工厂，有一个返回Car对象的静态类

      package com.jin.demo.DesignPatterns.Factory.SimpleFactory;
      
      /**
       * 简单工厂
       * @auther jinsx
       * @date 2019-05-15 09:06
       */
      public class CarSimpleFactory {
      	// 需要使用定义好的参数获取产品对象，没增加产品都需要修改次工厂方法
      	public static HFCar createHFCar(String type){
      		HFCar car = null;
      		switch (type){
      			case "roadster" :
      				car = new HFRoadster();
      				break;
      			case "truck" :
      				car = new HFTruck();
      				break;
      		}
      		return car;
      	}
      }
      

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    • 测试类https://dribbble.com/sanaslatvmcb/collections/4201092
      https://dribbble.com/nesmaoxclul/collections/4201094
      https://dribbble.com/sanaslatvmcb/collections/4201098
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      https://dribbble.com/nesmaoxclul/collections/4201110
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      https://dribbble.com/sanaslatvmcb/collections/4201117
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      https://dribbble.com/sanaslatvmcb/collections/4201120
      https://dribbble.com/sanaslatvmcb/collections/4201123
      https://dribbble.com/nesmaoxclul/collections/4201124
      https://dribbble.com/sanaslatvmcb/collections/4201128
      https://dribbble.com/nesmaoxclul/collections/4201130
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      https://dribbble.com/ratheuapo/collections/4201189
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      https://dribbble.com/ceeteanbkcxeb/collections/4201457

      package com.jin.demo.DesignPatterns.Factory.SimpleFactory;
      
      /**
       * 测试类
       * @auther jinsx
       * @date 2019-05-15 09:15
       */
      public class TestSimpleFactory {
      	public static void main(String[] args) {
      		// 来一个哈佛小跑
      		HFCar roadster = CarSimpleFactory.createHFCar("roadster");
      		roadster.run();
      		// 来一个哈佛小卡
      		HFCar truck = CarSimpleFactory.createHFCar("truck");
      		truck.run();
      	}
      }
      

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