1.简单工厂模式

定义了一个创建对象的类，由这个类来封装实力化对象的行为。

1.1类图

1.2 代码示例

pizza基类

package org.example.factory.simplefactory.pizzastore.pizza;

import lombok.Data;

@Data
public abstract class Pizza {

    String name = "";

    // 准备pizza的原材料
    public abstract void prepare();

    public void bake(){
        System.out.println(name +" 烘培 ");
    }

    public void cut(){
        System.out.println(name +" 裁剪 ");
    }

    public void box(){
        System.out.println(name +" 开始打包... ");
    }
}

奶酪披萨

package org.example.factory.simplefactory.pizzastore.pizza;

public class ChessPizza extends Pizza {
    @Override
    public void prepare() {
        System.out.println(" 奶酪披萨 准材料 ");
    }
}

希腊披萨

package org.example.factory.simplefactory.pizzastore.pizza;

public class GreekPizza extends Pizza {
    @Override
    public void prepare() {
        System.out.println(" 希腊披萨 准备材料");
    }
}

简单工厂类

package org.example.factory.simplefactory.pizzastore.order;

import org.example.factory.simplefactory.pizzastore.pizza.ChessPizza;
import org.example.factory.simplefactory.pizzastore.pizza.GreekPizza;
import org.example.factory.simplefactory.pizzastore.pizza.Pizza;

public class SimpleFactory {

    public Pizza createPizza(String type){
        Pizza pizza;
        do{
            if (type.equals("chess")) {
                pizza = new ChessPizza();
                pizza.setName("奶酪");
            } else if (type.equals("greek")){
                pizza = new GreekPizza();
                pizza.setName("希腊");
            } else {
                break;
            }
            System.out.println(" 披萨制作完成！ ");

            return pizza;
        }while (true);
        return null;
    }
}

订单类

package org.example.factory.simplefactory.pizzastore.order;

import org.example.factory.simplefactory.pizzastore.pizza.Pizza;

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

public class OrderPizza {

    SimpleFactory simpleFactory;

    Pizza pizza;

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

    public void setSimpleFactory(SimpleFactory simpleFactory){
        String type = "";
        do {
            this.simpleFactory = simpleFactory;
            type = getType();
            pizza = this.simpleFactory.createPizza(type);
            if (pizza != null) {
                pizza.prepare();
                pizza.bake();
                pizza.cut();
                pizza.box();
            } else {
                System.out.println(" 订购失败，没有这种类型的披萨～ ");
                break;
            }
        } while (true);
    }

    public String getType(){
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
            System.out.println(" 输入披萨的种类： ");
            return reader.readLine();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

披萨商店主程序入口

package org.example.factory.simplefactory.pizzastore.order;

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

        System.out.println(" 订单完成！ ");
    }
}

2.工厂方法模式

定义了一个创建对象的抽象方法，由子类决定要实例化的类，工厂方法模式将对象的实例化推迟到子类中去实现。

2.1 类图

2.2 代码示例

与简单工厂模式相比，在原有的披萨种类基础上添加了地区区分，在代码上修改了订单类，添加了两个订单子类。

订单类

package org.example.factory.factorymethod.pizzastore.order;


import org.example.factory.factorymethod.pizzastore.pizza.Pizza;

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

public class OrderPizza {

    Pizza pizza;

    public OrderPizza(){
        setSimpleFactory();
    }

    public void setSimpleFactory(){
        String loc = "";
        String type = "";
        do {
            loc = getType("地区");
            if (loc.equals("bj")) {
                type = getType("披萨种类");
                pizza = BJOrderPizza.createPizza(type);
            } else if (loc.equals("ld")) {
                type = getType("披萨种类");
                pizza = LDOrderPizza.createPizza(type);
            } else {
                System.out.println(" 订购失败，没有该地区～ ");
                break;
            }
            if (pizza != null) {
                pizza.prepare();
                pizza.bake();
                pizza.cut();
                pizza.box();
            } else {
                System.out.println(" 订购失败，没有这种类型的披萨～ ");
                break;
            }
        } while (true);
    }

    public String getType(String str){
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
            System.out.println(" 输入"+str+"： ");
            return reader.readLine();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

BJ订单类

package org.example.factory.factorymethod.pizzastore.order;

import org.example.factory.factorymethod.pizzastore.pizza.BJApplePizza;
import org.example.factory.factorymethod.pizzastore.pizza.BJCheesePizza;
import org.example.factory.factorymethod.pizzastore.pizza.Pizza;

public class BJOrderPizza {

    public static Pizza createPizza(String type){

        Pizza pizza = null;

        if (type.equals("apple")) {
            pizza = new BJApplePizza();
            pizza.setName("北京苹果披萨");
        } else if (type.equals("cheese")) {
            pizza = new BJCheesePizza();
            pizza.setName("北京奶酪披萨");
        }
        return pizza;
    }

}

LD订单类

package org.example.factory.factorymethod.pizzastore.order;

import org.example.factory.factorymethod.pizzastore.pizza.BJApplePizza;
import org.example.factory.factorymethod.pizzastore.pizza.BJCheesePizza;
import org.example.factory.factorymethod.pizzastore.pizza.Pizza;

public class LDOrderPizza {
    public static org.example.factory.factorymethod.pizzastore.pizza.Pizza createPizza(String type){

        Pizza pizza = null;

        if (type.equals("apple")) {
            pizza = new BJApplePizza();
            pizza.setName("伦敦苹果披萨");
        } else if (type.equals("cheese")) {
            pizza = new BJCheesePizza();
            pizza.setName("伦敦奶酪披萨");
        }
        return pizza;
    }
}

3.抽象工厂模式

定义一个interface用于创建相关或有依赖关系的对象簇，而无需指明具体的类；将简单工厂模式和工厂方法模式整合，将工厂抽象出两层，一个是抽象工厂，一个是具体的实现的工厂子类。

3.1 类图

3.2 代码示例

新增抽象工厂类

package org.example.factory.absfactory.pizzastore.order;

import org.example.factory.absfactory.pizzastore.pizza.Pizza;

//抽象工厂类
public interface AbsFactory {
    public Pizza createPizza(String type);
}

抽象工厂类的具体实现类

BJ工厂类用于创建对象并返回

package org.example.factory.absfactory.pizzastore.order;

import org.example.factory.absfactory.pizzastore.pizza.BJApplePizza;
import org.example.factory.absfactory.pizzastore.pizza.BJCheesePizza;
import org.example.factory.absfactory.pizzastore.pizza.Pizza;

public class BJFactory implements AbsFactory{

    @Override
    public Pizza createPizza(String type) {
        System.out.println(" 使用的是抽象工厂模式～ ");
        Pizza pizza = null;
        if (type.equals("apple")) {
            pizza = new BJApplePizza();
        } else if (type.equals("cheese")) {
            pizza = new BJCheesePizza();
        }
        return pizza;
    }

}

LD工厂类

package org.example.factory.absfactory.pizzastore.order;

import org.example.factory.absfactory.pizzastore.pizza.LDApplePizza;
import org.example.factory.absfactory.pizzastore.pizza.LDCheesePizza;
import org.example.factory.absfactory.pizzastore.pizza.Pizza;

public class LDFactory implements AbsFactory{

    @Override
    public Pizza createPizza(String type) {
        System.out.println(" 使用的是抽象工厂模式～ ");
        Pizza pizza = null;
        if (type.equals("apple")) {
            pizza = new LDApplePizza();
        } else if (type.equals("cheese")) {
            pizza = new LDCheesePizza() ;
        }
        return pizza;
    }

}

订单类

package org.example.factory.absfactory.pizzastore.order;

import org.example.factory.absfactory.pizzastore.pizza.Pizza;

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

public class OrderPizza {

    AbsFactory factory;

    public OrderPizza(AbsFactory factory){
        setFactory(factory);
    }

    private void setFactory(AbsFactory factory){
        Pizza pizza = null;
        String type = "";
        this.factory = factory;
        do {
            type = getType("披萨种类");
            pizza = factory.createPizza(type);
            if (pizza != null) {
                pizza.prepare();
                pizza.bake();
                pizza.cut();
                pizza.box();
            } else {
                System.out.println(" 订购失败 ");
                break;
            }
        } while (true);
    }

    private String getType(String str){
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
            System.out.println(" 输入"+str+"： ");
            return reader.readLine();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}