外观模式

什么是外观模式?

外观模式（Facade Pattern）门面模式，隐藏系统的复杂性，并向客户端提供了一个客户端可以访问系统的接口。这种类型的设计模式属于结构型模式，它向现有的系统添加一个接口，来隐藏系统的复杂性。
这种模式涉及到一个单一的类，该类提供了客户端请求的简化方法和对现有系统类方法的委托调用。

1232131.jpg

外观模式例子

用户注册完之后，需要调用阿里短信接口、邮件接口、微信推送接口。

public interface EamilSmsService {
      public void sendSms();
}
public class EamilSmsServiceImpl implements   EamilSmsService{
    public void sendSms() {
        System.out.println("发送邮件消息");
        
    }
}

//微信消息推送
public interface WeiXinSmsService {
  public void sendSms();    
}
public class EamilSmsServiceImpl implements   EamilSmsService{

    @Override
    public void sendSms() {
        System.out.println("发送邮件消息");
        
    }

}

//阿里短信消息
public interface AliSmsService {
    public void sendSms();
}
public class AliSmsServiceImpl implements AliSmsService {

    @Override
    public void sendSms() {
     System.out.println("支付宝发送消息...");
    }

}

//门面类
public class Computer {
    AliSmsService aliSmsService;
    EamilSmsService eamilSmsService;
    WeiXinSmsService weiXinSmsService;
    public Computer() {
        aliSmsService = new AliSmsServiceImpl();
        eamilSmsService = new EamilSmsServiceImpl();
        weiXinSmsService = new WeiXinSmsServiceImpl();
    }

    public void sendMsg() {
        aliSmsService.sendSms();
        eamilSmsService.sendSms();
        weiXinSmsService.sendSms();

    }

}

测试类

public class Client {

    public static void main(String[] args) {
        // AliSmsService aliSmsService= new AliSmsServiceImpl();
        // EamilSmsService eamilSmsService= new EamilSmsServiceImpl();
        // WeiXinSmsService weiXinSmsService= new WeiXinSmsServiceImpl();
        // aliSmsService.sendSms();
        // eamilSmsService.sendSms();
        // weiXinSmsService.sendSms();
        new Computer().sendMsg();
    }

}