没报错但是取不到值，只能打印出 学习
namespace app\index\controller;
use think\Controller;
class Test1 extends Controller
{
public function index(){
return 'shepi';
}
public function demo3()
{
return '学习'.$this->request->param( 'lesson');
}
public function demo4()
{
return '学习'.$this->request->get('lesson');
// return '学习'.Request::instance()->param('lesson');
}
}
