php 依赖注入的实现发邮件

<?php 

interface  Message{public function seed();}

class SeedEmail implements Message{     public function seed()    {         return  'seed email';    } }

class SeedSMS implements Message{    public function seed()    {        return 'seed sms';    }  }

class Order{     protected $messager = '';     function __construct(Message $message)    {        $this->messager = $message;     }    public function seed_msg()    {        return $this->messager->seed();    }}

//我们需要发送邮件的时候

$message = new SeedEmail();

//将邮件发送对象作为参数传递给Order

$Order = new Order($message);

$Order->seed_msg(); 

 //我们需要发送短信的时候

$message = new SeedSMS();

$Order = new Order($message);

$Order->seed_msg();