Laravel 5.7导入Excel文件说明

Question

我绝对不是laravel的新手。有人可以帮助我逐行理解这些代码，这是做什么的，等等。这是用于将excel文件导入数据库。

对于控制器：

public function import(Request $request)
{
    $import = Excel::import(new ResidentImport, request()->file('import_file'));
    return redirect('/importing')->with('success', 'Imported Successfully!');
}

该模型有什么用？

public function model(array $row)
{
    return new Resident([
        'resident_fname' => $row[0],
        'resident_lname' => $row[1],
        'resident_mi'    => $row[2],
        'resident_dob'   => \PhpOffice\PhpSpreadsheet\Shared\Date::excelToDateTimeObject($row['3']),
        'role'           => $row[4],
        'resident_age'   => $row[5],
        'resident_address'  => $row[6],
        'resident_contact'  => $row[7],
        'resident_email'    => $row[8],
        'resident_purok'    => $row[9],
        'resident_status'   => $row[10],
        'resident_gender'   => $row[11],
        'resident_religion' => $row[12],
        'ResidentVoter_status'  => $row[13],

    ]);
}