设计模式——工厂模式

简单工厂模式

/*
         简单工厂模式：完全冗余生产，容易混乱
             通过一个工厂内实现所有的部件发送消息
        */

public class FactorySimple {
     //简单工厂模式：内部无该具体类的属性
     public void sendMSG(String type,String message) {
         if ("Wechat".equals(type)) {
             new WechatMSG().sendMsg(message);
         }else if ("PhoneMSG".equals(type)) {
             new WechatMSG().sendMsg(message);
         }else if ("Email".equals(type)) {
             new EmailMSG().sendMsg(message);
         }else {
             //System.out.println("mached error");
             throw new NoSuchFieldError("没有该对象实现类");
         }
     }
}

//
         FactorySimple fSimple = new FactorySimple();
         fSimple.sendMSG("Wechat", "hello wechat 简单工厂模式");
         fSimple.sendMSG("PhoneMSG", "hello phone 简单工厂模式");
         fSimple.sendMSG("Email", "hello email 简单工厂模式");
         //缺点：增加业务需求，如增加发送邮件，需要修改工厂类中的生产方法

改进：抽象工厂模式

/*
          抽象工厂模式：专业化生产，浪费资源，每次都需要新建工厂
              通过不同工厂专业化实现特有部件发送消息
         */
  

public class WechatFactory implements Producer{

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

public class PhoneFactory implements Producer{

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

        WechatFactory wFactory = new WechatFactory();
         WechatMSG wMsg = wFactory.create();
         wMsg.sendMsg("wechat 抽象工厂模式");
         //增加需求，实现+新建对应的工厂类
         new PhoneFactory().create().sendMsg("phone 抽象工厂模式");

改进：适配器模式

//对象的适配器模式： 一超多能

public class FactoryAbstract {
     private SendMSG sendMSG;
     public FactoryAbstract(SendMSG sendMSG) {
         this.sendMSG = sendMSG;
     }
     //方法名称跟实际业务关系
     public void sendMSG(String message) {
         this.sendMSG.sendMsg(message);
     }
}

public interface SendMSG {
     public void sendMsg(String message);
}

         FactoryAbstract fAbstract = new FactoryAbstract(new WechatMSG());
         fAbstract.sendMSG("hello wechat");
        
         new FactoryAbstract(new EmailMSG()).sendMSG("hello phone");
         //新增发送，只需实例化对象
         new FactoryAbstract(new DingDing()).sendMSG("hello dingding");