abstract：<?php interface  Message{public function seed();}class SeedEmail implements Message{     public function seed()    {         return 

<?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();    }}

//我們需要發(fā)送郵件的時(shí)候

$message = new SeedEmail();

//將郵件發(fā)送對象作為參數(shù)傳遞給Order

$Order = new Order($message);

$Order->seed_msg(); 

 //我們需要發(fā)送短信的時(shí)候

$message = new SeedSMS();

$Order = new Order($message);

$Order->seed_msg();

Correcting teacher：查無此人Correction time：2020-02-27 15:33:10
Teacher's summary：完成的不錯。依賴注入現(xiàn)在很流行，多了解。繼續(xù)加油