Java 工厂模式学习

工厂模式分三种：简单工厂、工厂方法、抽象工厂。其中抽象工厂是用于多个产品族的情况。所谓产品族就是不同产品组成的有机整体，各不同产品之间相互依赖。打个比方，一台电脑有CPU、主板、内存和硬盘等，这些不同产品组成了一个产品族。就好比Dell和HP要把这些产品进行不同的组装，这时就需要用到抽象工厂。以下是代码演示：

简单工厂，可以用反射实现：

首先定义产品的抽象接口

package com.demo.SimpleFactory;

public interface CPU {
    public void run();
}

定义具体产品

package com.demo.SimpleFactory;

public class Intel implements CPU {

    @Override
    public void run() {
        // TODO Auto-generated method stub
        System.out.println("This is Intel!");
    }

}

package com.demo.SimpleFactory;

public class Amd implements CPU {

    @Override
    public void run() {
        // TODO Auto-generated method stub
        System.out.println("This is Amd!");
    }

}

定义工厂类

package com.demo.SimpleFactory;

public class Factory {
    public static CPU create(String str) {
        CPU c = null;
        try {
            c = (CPU) Class.forName("com.demo.SimpleFactory." + str)
                    .newInstance();

        } catch (Exception e) {
            e.printStackTrace();
        }
        return c;
    }
}

测试如下

package com.demo.SimpleFactory;

public class Test {
    public static void main(String[] args){
        CPU c=Factory.create("Amd");
        c.run();
    }
}

打印结果：

This is Amd!

工厂方法

首先定义产品的抽象接口

package com.demo.SimpleFactory;

public interface CPU {
    public void run();
}

定义具体产品

package com.demo.SimpleFactory;

public class Intel implements CPU {

    @Override
    public void run() {
        // TODO Auto-generated method stub
        System.out.println("This is Intel!");
    }

}

package com.demo.SimpleFactory;

public class Amd implements CPU {

    @Override
    public void run() {
        // TODO Auto-generated method stub
        System.out.println("This is Amd!");
    }

}

定义抽象工厂，具体现实由其子类负责

package com.demo.FactoryMethod;

public interface FactoryMethod {
    public CPU create();
}

具体子类工厂

package com.demo.FactoryMethod;

public class AmdFactory implements FactoryMethod {

    @Override
    public  CPU create() {
        // TODO Auto-generated method stub
        return new Amd();
    }

}

package com.demo.FactoryMethod;

public class IntelFactory implements FactoryMethod {
    public  CPU create() {
        return new Intel();
    }
}

测试

package com.demo.FactoryMethod;

public class Test {

    public static void main(String[] args) {
        FactoryMethod af=new IntelFactory();
        CPU c=af.create();
        c.run();
    }
}

打印结果：

This is Intel!

抽象工厂

首先定义产品的抽象接口

package com.demo.SimpleFactory;

public interface CPU {
    public void run();
}

定义具体产品

package com.demo.SimpleFactory;

public class Intel implements CPU {

    @Override
    public void run() {
        // TODO Auto-generated method stub
        System.out.println("This is Intel!");
    }

}

package com.demo.SimpleFactory;

public class Amd implements CPU {

    @Override
    public void run() {
        // TODO Auto-generated method stub
        System.out.println("This is Amd!");
    }

}

package com.demo.AbstractFactory;

public interface Memory {
    public void read(String str);
}

package com.demo.AbstractFactory;

public class KingstonMemory implements Memory {

    public KingstonMemory() {
        // TODO Auto-generated constructor stub
    }

    @Override
    public void read(String str) {
        // TODO Auto-generated method stub
        System.out.println("Kingston Read data is:"+str);
    }

}

package com.demo.AbstractFactory;

public class AdataMemory implements Memory {

    public AdataMemory() {
        // TODO Auto-generated constructor stub
    }

    @Override
    public void read(String str) {
        // TODO Auto-generated method stub
        System.out.println("Adata read data is:"+str);
    }

}

定义抽象工厂

package com.demo.AbstractFactory;

public interface AbstractFactory {

    public CPU createCPU();

    public Memory createMemory();
}

不同子类产生不同产品族

package com.demo.AbstractFactory;

public class DellFactory implements AbstractFactory {

    @Override
    public CPU createCPU() {
        // TODO Auto-generated method stub
        return new Intel();
    }

    @Override
    public Memory createMemory() {
        // TODO Auto-generated method stub
        return new KingstonMemory();
    }

}

package com.demo.AbstractFactory;

public class HPFactory implements AbstractFactory {

    @Override
    public CPU createCPU() {
        // TODO Auto-generated method stub
        return new Amd();
    }

    @Override
    public Memory createMemory() {
        // TODO Auto-generated method stub
        return new AdataMemory();
    }

}

测试

package com.demo.AbstractFactory;

public class Test {
    public static void main(String[] args){
        AbstractFactory hp=new HPFactory();
        CPU cpu=hp.createCPU();
        Memory memory=hp.createMemory();
        cpu.run();
        memory.read("Pass");
    }
}

打印结果：

This is Amd!
Adata read data is:Pass