设计模式 - 工厂模式

简单工厂模式

• 抽象产品角色（牛奶）

package com.lushwe.pattern.factory;

/**
 * @Author Jack
 * @Description
 * @Date Create in 2018/6/21 14:43
 */
public interface Milk {

    String getName();
}

• 工厂角色

public class SimpleFactory {

    public Milk getMilk(String name) {
        if ("telunsu".equalsIgnoreCase(name)) {
            return new Telunsu();
        } else if ("mengniu".equalsIgnoreCase(name)) {
            return new Mengniu();
        }
        throw new IllegalArgumentException("name[" + name + "] is invalid");
    }
}

• 具体产品角色

// 具体角色1
public class Mengniu implements Milk {
    @Override
    public String getName() {
        return "蒙牛";
    }
}

// 具体角色2
public class Telunsu implements Milk {

    public String getName() {
        return "特仑苏";
    }

}

• 测试简单工厂模式

public class SimpleFactoryTest {

    public static void main(String[] args) {
        SimpleFactory factory = new SimpleFactory();
        Milk telunsu = factory.getMilk("telunsu");
        Milk mengniu = factory.getMilk("mengniu");
        System.out.println("telunsu.name = " + telunsu.getName());
        System.out.println("mengniu.name = " + mengniu.getName());
    }
}

• 显示日志

milk.name = 特仑苏
milk.name = 蒙牛

工厂方法模式

• 工厂抽象

public interface Factory {

    Milk getMilk();
}

• 具体工厂

// 具体工厂1
public class MengniuFactory implements Factory {
    @Override
    public Milk getMilk() {
        return new Mengniu();
    }
}

// 具体工厂2
public class TelunsuFactory implements Factory {
    @Override
    public Milk getMilk() {
        return new Telunsu();
    }
}

• 测试工厂方法模式

public class FuncFactoryTest {

    public static void main(String[] args) {

        Factory factory;
        Milk milk;

        factory = new TelunsuFactory();
        milk = factory.getMilk();
        System.out.println("milk1.name = " + milk.getName());

        factory = new MengniuFactory();
        milk = factory.getMilk();
        System.out.println("milk2.name = " + milk.getName());

    }
}

• 显示日志

milk1.name = 特仑苏
milk2.name = 蒙牛

抽象工厂模式

• 工厂抽象

public abstract class AbstractFactory {

    public abstract Milk getTelunsu();

    public abstract Milk getMengniu();

}

• 具体工厂

public class MilkFactory extends AbstractFactory {

    @Override
    public Milk getTelunsu() {
        return new Telunsu();
    }

    @Override
    public Milk getMengniu() {
        return new Mengniu();
    }
}

• 测试抽象工厂

public class AbstractFactoryTest {

    public static void main(String[] args) {

        MilkFactory factory = new MilkFactory();

        Milk telunsu = factory.getTelunsu();
        Milk mengniu = factory.getMengniu();

        System.out.println(telunsu.getName());
        System.out.println(mengniu.getName());

    }
}

• 显示日志

特仑苏
蒙牛