学习yii2.0——依赖注入

<?php
namespace app\controllers;

use yii\web\Controller;
use yii\di\Container;

class A 
{
	public $name = "hello";
}

class B 
{
	private $_obj;
	//这里要注意声明$a的类型
	public function __construct(A $a) 
	{
		$this->_obj = $a;
	}

	public function Say() 
	{
		echo $this->_obj->name;
	}
}

class HelloController extends Controller 
{
	public function actionIndex()
	{
		$container = new Container();
		$b = $container->get("app\controllers\B");
		$b->Say();   //hello

		//上面的代码类似于
		// $a = new A();
		// $b = new B($a);
		// $b->Say();
	}
}