工厂方法模式分为三种:普通工厂模式、多个工厂方法模式、静态工厂方法模式。
(1)普通工厂模式,就是建立一个工厂类,对实现了同一接口的一些类进行实例的创建。
package com.shuang.factory;
public interface Sender {
public void send();
}
package com.shuang.factory;
public class MailSender implements Sender {
public void send() {
System.out.println("mailSender");
}
}
package com.shuang.factory;
public class SmsSender implements Sender {
@Override
public void send() {
System.out.println("smsSender");
}
}
package com.shuang.factory;
public class SendFactory {
public Sender produce(String name){
if(name.equals("sms")){
return new SmsSender();
}else if(name.equals("mail")){
return new MailSender();
}else{
System.out.println("没有此对象");
return null;
}
}
public static void main(String[] args) {
SendFactory factory=new SendFactory();
Sender s=factory.produce("sms");
s.send();
}
}
c++版如下:
#include<iostream>
using namespace std;
class Fruit
{
public:
virtual void getFruit()=0;
};
class Banana:public Fruit
{
public:
virtual void getFruit()
{
cout<<"我是香蕉。。。。"<<endl;
}
};
class Apple:public Fruit
{
public:
virtual void getFruit()
{
cout<<"我是苹果"<<endl;
}
};
class Factory
{
public:
Fruit *create(char *p)
{
if(strcmp(p,"banana")==0)
{
return new Banana;
}
else if(strcmp(p,"apple")==0)
{
return new Apple;
}
else
{
printf("不支持\n");
return NULL;
}
}
};
void main()
{
Factory *f=new Factory;
Fruit * fruit=NULL;
fruit=f->create("banana");
fruit->getFruit();
delete fruit;
fruit=f->create("apple");
fruit->getFruit();
delete fruit;
delete f;
system("pause");
}
(2)多个工厂方法模式,是对普通工厂方法模式的改进,在普通工厂方法模式中,如果传递的字符串出错,则不能正确创建对象,而多个工厂方法模式是提供多个工厂方法,分别创建对象。
将上面代码的SendFactory作如下修改即可
package com.shuang.manyfactory;
public class SendFactory {
public Sender produceMail(){
return new MailSender();
}
public Sender produceSms(){
return new SmsSender();
}
public static void main(String[] args) {
SendFactory factory=new SendFactory();
Sender s=factory.produceSms();
s.send();
}
}
c++版如下:
#include<iostream>
using namespace std;
class Fruit
{
public:
virtual void sayname()=0;
};
class Banana:public Fruit
{
public:
void sayname()
{
cout<<"我是香蕉"<<endl;
}
};
class Apple:public Fruit
{
public:
void sayname()
{
cout<<"我是Apple"<<endl;
}
};
class AbFactory
{
public:
virtual Fruit *CreateProduct()=0;
};
class BananaFactory:public AbFactory
{
public:
virtual Fruit *CreateProduct()
{
return new Banana;
}
};
class AppleFactory:public AbFactory
{
public:
virtual Fruit *CreateProduct()
{
return new Apple;
}
};
void main()
{
AbFactory *factory=NULL;
Fruit *fruit=NULL;
factory=new BananaFactory;
fruit=factory->CreateProduct();
fruit->sayname();
delete fruit;
factory=new AppleFactory;
fruit=factory->CreateProduct();
fruit->sayname();
delete fruit;
delete factory;
system("pause");
}
(3)静态工厂方法模式
静态工厂方法模式,将上面的多个工厂方法模式里的方法置为静态的,不需要创建实例,直接调用即可。
package com.shuang.staticfactory;
public class SendFactory {
public static Sender produceMail(){
return new MailSender();
}
public static Sender produceSms(){
return new SmsSender();
}
public static void main(String[] args) {
Sender s=SendFactory.produceSms();
s.send();
}
}