abstract：//構(gòu)造函數(shù)實現(xiàn)依賴注入class Boy1{    private $girl = null;    public function __construct(Girl $girl)    {        $this->girl = $girl;    }  

//構(gòu)造函數(shù)實現(xiàn)依賴注入

class Boy1
{
   private $girl = null;
   public function __construct(Girl $girl)
   {
       $this->girl = $girl;
   }

   public function getInfo()
   {
       return "我的女朋友".$this->girl->work();
   }
}
//類外實例化Girl;
$girl = new Girl;
$boy1 = new Boy1($girl);
echo $boy1->getInfo();

echo "<hr>";

//普通方法注入
class Boy2
{
   public function buy(Girl $girl)
   {
       return "我的女朋友".$girl->hobby();
   }
}
$girl = new Girl;
$boy2 = new Boy2;
echo $boy2->buy($girl);

在類外部實例化優(yōu)勢 減少類與類之間耦合性

Correcting teacher：天蓬老師Correction time：2019-05-28 15:52:29
Teacher's summary：依賴注入的重點在于外部對象的實例化的時機(jī), 理解了這個就好了