外观模式

为子系统种的一组接口提供一个一致的界面，用来访问子系统种的一群接口 又称为门面模式<br />子接口太多，操作类里面一大堆，将一大堆接口封装一下，外部统一调用封装后的接口，<br />比如说，去医院看病，挂号，门诊，化验，取药，好几个地方，需要病人每个都接触一遍，外观模式就是，增加一个接待员，病人直接找接待员就好，接待员负责接触其他科室，![image.png](https://cdn.nlark.com/yuque/0/2021/png/22438777/1635242127836-170a3bb5-98d7-452f-8082-ffe3dce6fea3.png#clientId=u3c0b05b6-70e0-4&from=paste&height=463&id=ud535302d&margin=%5Bobject%20Object%5D&name=image.png&originHeight=463&originWidth=655&originalType=binary&ratio=1&size=70474&status=done&style=none&taskId=uf9512413-db26-4a59-a266-9b70a707143&width=655)

<?php
class SubSystemOne
{
    public function MethodOne()
    {
        echo '子系统方法一';
    }
}
class SubSystemTwo
{
    public function MethodTwo()
    {
        echo '子系统方法二';
    }
}
class SubSystemThree
{
    public function MethodThree()
    {
        echo '子系统方法三';
    }
}
class SubSystemFour
{
    public function MethodFour()
    {
        echo '子系统方法四';
    }
}
//外观类
class Facade
{
    public $SubSystemOne;
    public $SubSystemTwo;
    public $SubSystemThree;
    public $SubSystemFour;
    public function __construct()
    {
        $this->SubSystemOne = new SubSystemOne();
        $this->SubSystemTwo = new SubSystemTwo();
        $this->SubSystemThree = new SubSystemThree();
        $this->SubSystemFour = new SubSystemFour();
    }
    public function MethodA()
    {
        echo '系统A';
        $this->SubSystemOne->MethodOne();
        $this->SubSystemTwo->MethodTwo();
    }
    public function MethodB()
    {
        echo '系统B';
        $this->SubSystemThree->MethodThree();
        $this->SubSystemFour->MethodFour();
    }
}
/**
 * 操作类
 */
class ClassName
{
    public function main()
    {
        $Facade = new Facade();
        $Facade->MethodA();
        $Facade->MethodB();
    }
}
$name= new ClassName();
$name->main();