老师，我在windows上编写代码，怎么我读取excel文件时，文件明明在那，但就是报错文件不存在呢

header("Content-Type:text/html;charset=utf-8");
$dir = dirname(__FILE__);
require $dir . DIRECTORY_SEPARATOR . "phpexcel/PHPExcel/IOFactory.php";
$filename = $dir . DIRECTORY_SEPARATOR . "data/能源计量数据直报/电/重点用户监控数据2016-01-16.xls";

$inputFileType = PHPExcel_IOFactory::identify($filename);
$objReader = PHPExcel_IOFactory::createReader($inputFileType);
$objPHPExcel = $objReader->load($filename);

$objWorksheet = $objPHPExcel->getActiveSheet();
$highestRow = $objWorksheet->getHighestRow();
//$highestColumn = $objWorksheet->getHighestColumn();

$arr = array(5 => 'E', 7 => 'G', 8 => 'H', 15 => 'O', 16 => 'P');
$res = array();
for ($row = 2; $row <= $highestRow; $row++)
{
    for ($column = 0; $column < count($arr); $column++)
    {
        $var = $objWorksheet->getCellByColumnAndRow($column, $row)->getValue();
        $res[$row - 2][$column] = $var;
    }
}

print_r($res);

但是报错：

Fatal error: Uncaught PHPExcel_Reader_Exception: Could not open H:\Users\LiuQi\PhpstormProjects\Study\jxsenergy\data/能源计量数据直报/电/重点用户监控数据2016-01-16.xls for reading! File does not exist. in H:\Users\LiuQi\PhpstormProjects\Study\jxsenergy\phpexcel\PHPExcel\Reader\Excel5.php:433 Stack trace: #0 H:\Users\LiuQi\PhpstormProjects\Study\jxsenergy\phpexcel\PHPExcel\IOFactory.php(269): PHPExcel_Reader_Excel5->canRead('H:\\Users\\LiuQi\\...') #1 H:\Users\LiuQi\PhpstormProjects\Study\jxsenergy\phpexcel\PHPExcel\IOFactory.php(206): PHPExcel_IOFactory::createReaderForFile('H:\\Users\\LiuQi\\...') #2 H:\Users\LiuQi\PhpstormProjects\Study\jxsenergy\import.php(13): PHPExcel_IOFactory::identify('H:\\Users\\LiuQi\\...') #3 {main} thrown in H:\Users\LiuQi\PhpstormProjects\Study\jxsenergy\phpexcel\PHPExcel\Reader\Excel5.php on line 433