php 魔术方法 __tostring() __invoke()

//__tostring() 用于屏蔽错误信息，当需要输出错误信息时，用本函数内返回的字符串代替
//__invoke() 用于屏蔽错误信息，当把对象当作函数调用时，会执行本函数

<?php 
header("Content-type: text/html; charset=utf-8");
//设置中国时区
date_default_timezone_set('PRC');
// $str='mypic.jpg';
// echo strlen($str);
// echo date('YmdHis').substr($str,stripos($str,'.'),strlen($str)-stripos($str,'.'))."<br>";
// echo md5('123');

class Student
{
    protected $name="Karl";
    private $age = 24;
    public $edu = "大专";
    public function showInfo()
    {
        echo "<h2>遍历对象属性</h2>";
        foreach($this as $key=>$value){
            echo "\$this->{$key} = {$value}<br>";
        }
    }
    public function __tostring()
    {
        return "Happy birthday!";
    }
    public function __invoke()
    {
        return "I come from invoke!";
    }
    
}
$obj1 = new Student();
// $obj2 = clone $obj1;
// $obj3 = clone $obj1;
// var_dump($obj1,$obj2,$obj3);

// $obj1->showInfo();
var_dump($obj1);
echo $obj1();
// echo 110+"abc";