PHP之创建对象的基本形式

class p_obj{    public $val;    public function func(){        echo "new obj";    }}

$obj_one = new p_obj();

$obj = "p_obj";$obj_two = new $obj();

$obj_three = new self;//self指代类本身，这行代码只能在类内部使用

//通过对象创建对象$obj_four = new $obj_one;