mysqli的异常处理功能？

mysqli的异常处理功能？
class check{
                        private $host;
                        private $name;
                        private $paw;
                        public $res;
                        function connect($host,$name,$paw){
//                                var_dump($host,$name,$paw);exit();
                                $this->res = @new mysqli($host,$name,$paw);
                                //
                                if(!$this->res){
                                        throw new Exception("MySQL connect is error!");
                                }
                        }

                }
               
                try {
                        $a = new check();
                        $a->connect("localhost","root","123jodjg");

                }catch (Exception $e){
                        echo $e->getMessage();
                }

这个是代码。如果不用mysqli来做。用mysql_connect这样的函数来做就没问题的