php怎么导出数据库的数据并转为excel表格

$conn = mysqli_connect($servername, $username, $passWord, $dbname);
if (!$conn) {
    die("连接失败: " . mysqli_connect_error());
}

$sql = "SELECT * FROM `table_name`";
$result = mysqli_query($conn, $sql);

//创建PHPExcel对象
$objPHPExcel = new PHPExcel();

//设置Excel文件属性
$objPHPExcel->getProperties()
    ->setCreator("your name")
    ->setLastModifiedBy("your name")
    ->setTitle("title")
    ->setSubject("subject")
    ->setDescription("description")
    ->seTKEywords("keywords")
    ->setCateGory("category");

//设置当前活动表格
$objPHPExcel->setActiveSheetIndex(0);

//循环遍历查询结果，将数据写入Excel表格
$i = 1;
while ($row = mysqli_fetch_array($result)) {
    $objPHPExcel->getActiveSheet()->setCellValue('A' . $i, $row['column1']);
    $objPHPExcel->getActiveSheet()->setCellValue('B' . $i, $row['column2']);
    $i++;
}

header('Content-Type: application/vnd.ms-excel');
header('Content-Disposition: attachment;filename="filename.xls"');
header('Cache-Control: max-age=0');
$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel5');
$objWriter->save('php://output');

$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel5');
$objWriter->save('file_path/filename.xls');