设计模式之：简单工厂

有一个案例来推导出简单工厂模式：

 Pizza 类

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/**  * @description: 披萨类（包含基础的 准备原料、制作、切割、打包等操作）  * @author: abel.he  * @date: 2023-08-24  **/ public class Pizza {     /**      * pizza名称      */     private String pizzaName;       /**      *   准备原材料      */     public void prepare(){         System.out.println(pizzaName + "： 准备原材料");     }       /**      * 烘烤      */     void bake() {         System.out.println(pizzaName + "： 烘烤");     }       /**      * 剪切      */     void cut() {         System.out.println(pizzaName + "： 剪切");     }       /**      * 打包      */     void box() {         System.out.println(pizzaName + "： 打包");     }     public void setPizzaName(String pizzaName){         this.pizzaName = pizzaName;     }   }

ChessPizza类：

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/**  * @description: 芝士披萨  * @author: abel.he  * @date: 2023-08-24  **/ public class ChessPizza extends Pizza {       }

GreekPizza类

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/**  * @description: 希腊披萨  * @author: abel.he  * @date: 2023-08-24  **/ public class GreekPizza extends Pizza{         }

OrderPizza

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/**  * @description: 蛋糕店  * @author: abel.he  * @date: 2023-08-24  **/ public class OrderPizza {       public static void main(String[] args) {         Pizza pizza = null;         do {             String type = getType();             if ("chess".equals(type)) {                 pizza = new ChessPizza();                 pizza.setPizzaName("芝士披萨");             } else if ("greek".equals(type)) {                 pizza = new GreekPizza();                 pizza.setPizzaName("希腊披萨");             } else {                 System.out.println("订单结束");                 break;             }               pizza.prepare();             pizza.bake();             pizza.cut();             pizza.box();         } while (true);     }       private static String getType() {         Scanner scanner = new Scanner(System.in);         System.out.println("请输入想制作的披萨：");         return scanner.nextLine();     }   }

 优缺点说明：

• 优点：容易理解，简单易操作
• 缺点：违反了opc原则，对扩展开放，对修改关闭。即当我们增加新的功能时，尽量不修改代码，或者尽量少修改代码
  • 比如我们增加一个新的Pizza的种类(Pepper披萨)，我们需要增加Pepper类，订单Pizza也需要增加判断
• 改进思路：把创建的对象封装到一个类中，这样我们有新的Pizza种类时，只需要修改该类就可以了，其他创建到Pizza对象的代码就不需要修改了-》简单工厂模式

改成简单工程模式实现

 

Pizza

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package org.example.creation_type.simple_factory.optimize;   /**  * 披萨类  *  * @author abel.he  * @since 2023-09-02  */ public class Pizza {       /**      * pizza名称      */     private String pizzaName;       /**      *   准备原材料      */     public void prepare(){         System.out.println(pizzaName + "： 准备原材料");     }       /**      * 烘烤      */     void bake() {         System.out.println(pizzaName + "： 烘烤");     }       /**      * 剪切      */     void cut() {         System.out.println(pizzaName + "： 剪切");     }       /**      * 打包      */     void box() {         System.out.println(pizzaName + "： 打包");     }     public void setPizzaName(String pizzaName){         this.pizzaName = pizzaName;     }     }

CheesePizza

 

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public class CheesePizza extends Pizza {     public CheesePizza() {         super.setPizzaName("奶酪披萨");     }   }

 

GreekPizza

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public class GreekPizza extends Pizza {       public GreekPizza() {         setPizzaName("希腊披萨");     }   }

　SimpleFactory

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public class SimpleFactory {       /**      * 返回pizza数据      *      * @param type 要创建的pizza种类      * @return      */     public Pizza createPizza(String type) {         System.out.println("使用简单工厂模式");         Pizza pizza = null;         if ("chess".equals(type)) {             pizza = new CheesePizza();             pizza.setPizzaName("芝士披萨");         } else if ("greek".equals(type)) {             pizza = new GreekPizza();             pizza.setPizzaName("希腊披萨");         }         return pizza;     }   }

　OrderPizza1

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public class OrderPizza1 {       // 定义一个简单工厂对象     SimpleFactory simpleFactory;     Pizza pizza = null;       // 构造器传参     public OrderPizza1(SimpleFactory simpleFactory) {         setFactory(simpleFactory);     }       private void setFactory(SimpleFactory simpleFactory) {         // 用户属于         String orderType = "";           do {             orderType = getType();             Pizza pizza = simpleFactory.createPizza(orderType);             if (Objects.nonNull(pizza)) {                 pizza.prepare();                 pizza.bake();                 pizza.cut();                 pizza.box();             } else {                 System.out.println("披萨订购失败");                 break;             }         } while (true);     }       /**      * 获取要订阅的pizza      *      * @return pizza      */     private String getType() {         BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));         try {             System.out.print("请输入要订购的披萨：");             String pizzaType = reader.readLine();             System.out.println("要订阅的pizza种类：" + pizzaType);             return pizzaType;         } catch (IOException e) {             e.printStackTrace();             return "";         }     } }

PizzaStore

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public class PizzaStore {       public static void main(String[] args) {         new OrderPizza1(new SimpleFactory());     }   }