设计模式之二工厂模式之一简单工厂模式

简单工厂模式案例

pizza 的订购项目

public class OrderPizza {

    /*public OrderPizza() {
        Pizza pizza = null;
        String orderType;
        do {
            orderType =  getType();
            if (orderType.equals("greek")) {
                pizza = new GreekPizza();
                pizza.setName("希腊披萨");
            } else if (orderType.equals("cheese")) {
                pizza = new CheesePizza();
                pizza.setName("奶酪披萨");
            } else if (orderType.equals("pepper")) {
                pizza = new CheesePizza();
                pizza.setName("胡椒披萨");
            } else {
                break;
            }

            pizza.prepare();
            pizza.bake();
            pizza.cut();
            pizza.box();
        } while (true);
    }*/
传统方式的优缺点
1）优点是比较好理解，简单易操作
2）缺点是违反设计模式的ocp原则，及对扩展开放，对修改关闭。即当我们给类增加新功能的时候，尽量不改代码，或者尽可能少修改代码
3)新增加Pipper类，只要是订购Pizzer的代码都需要修改

 

4）改进思路

分析：修改代码可以接受，创建pizza的代码有多出就不好

思路：把创建Pizza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。其他有创建Pizza对象的代码就不需要修改了。

 

 

 

public class SimpleFactory {
    public Pizza createPizza(String orderType) {
        Pizza pizza = null;
        System.out.println("使用简单工厂模式");
        if (orderType.equals("greek")) {
            pizza = new GreekPizza();
            pizza.setName("希腊披萨");
        } else if (orderType.equals("cheese")) {
            pizza = new CheesePizza();
            pizza.setName("奶酪披萨");
        } else if (orderType.equals("pepper")) {
            pizza = new CheesePizza();
            pizza.setName("胡椒披萨");
        }
        return pizza;
    }

    //静态方法，也就是只有一个工厂
    public static Pizza createPizza2(String orderType) {
        Pizza pizza = null;
        System.out.println("使用简单工厂模式");
        if (orderType.equals("greek")) {
            pizza = new GreekPizza();
            pizza.setName("希腊披萨");
        } else if (orderType.equals("cheese")) {
            pizza = new CheesePizza();
            pizza.setName("奶酪披萨");
        } else if (orderType.equals("pepper")) {
            pizza = new CheesePizza();
            pizza.setName("胡椒披萨");
        }
        return pizza;
    }
}

package com.hy.factory.simplefactory.pizzastore.order;

import com.hy.factory.simplefactory.pizzastore.pizza.CheesePizza;
import com.hy.factory.simplefactory.pizzastore.pizza.GreekPizza;
import com.hy.factory.simplefactory.pizzastore.pizza.Pizza;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 * @author hanyong
 * @date 2020/10/31 20:41
 */
public class OrderPizza {

    /*public OrderPizza() {
        Pizza pizza = null;
        String orderType;
        do {
            orderType =  getType();
            if (orderType.equals("greek")) {
                pizza = new GreekPizza();
                pizza.setName("希腊披萨");
            } else if (orderType.equals("cheese")) {
                pizza = new CheesePizza();
                pizza.setName("奶酪披萨");
            } else if (orderType.equals("pepper")) {
                pizza = new CheesePizza();
                pizza.setName("胡椒披萨");
            } else {
                break;
            }

            pizza.prepare();
            pizza.bake();
            pizza.cut();
            pizza.box();
        } while (true);
    }*/

    SimpleFactory simpleFactory;
    Pizza pizza;


    public OrderPizza(SimpleFactory simpleFactory) {
        setSimpleFactory(simpleFactory);
    }

    public void setSimpleFactory(SimpleFactory simpleFactory) {
        String orderType = "";
        this.simpleFactory = simpleFactory;
        do {
            orderType = getType();
            pizza = this.simpleFactory.createPizza(orderType);
            //输出pizza
            if (pizza != null) { //订购成功
                pizza.prepare();
                pizza.bake();
                pizza.cut();
                pizza.box();
            } else {
                System.out.println(" 订购披萨失败 ");
                break;
            }
        } while (true);
    }


    // 写一个方法，可以获取客户希望订购的披萨种类
    private String getType() {
        try {
            BufferedReader strin = new BufferedReader(new InputStreamReader(System.in));
            System.out.println("input pizza 种类:");
            String str = strin.readLine();
            return str;
        } catch (IOException e) {
            e.printStackTrace();
            return "";
        }
    }
}