数组转xls格式的excel文件

/**
 * 数组转xls格式的excel文件
 * @param  array  $data      需要生成excel文件的数组
 * @param  string $filename  生成的excel文件名
 *      示例数据：
$data = array(
array(NULL, 2010, 2011, 2012),
array('Q1',   12,   15,   21),
array('Q2',   56,   73,   86),
array('Q3',   52,   61,   69),
array('Q4',   30,   32,    0),
);
 */
function create_xls($data,$filename='simple.xls'){
    ini_set('max_execution_time', '0');
    $filename=str_replace('.xls', '', $filename).'.xls';
    $phpexcel = new \PHPExcel();
    $phpexcel->getProperties()
        ->setCreator("Maarten Balliauw")
        ->setLastModifiedBy("Maarten Balliauw")
        ->setTitle("Office 2007 XLSX Test Document")
        ->setSubject("Office 2007 XLSX Test Document")
        ->setDescription("Test document for Office 2007 XLSX, generated using PHP classes.")
        ->setKeywords("office 2007 openxml php")
        ->setCategory("Test result file");
    $phpexcel->getActiveSheet()->fromArray($data);
    $phpexcel->getActiveSheet()->setTitle('Sheet1');
    $phpexcel->setActiveSheetIndex(0);
    header('Content-Type: application/vnd.ms-excel');
    header("Content-Disposition: attachment;filename=$filename");
    header('Cache-Control: max-age=0');
    header('Cache-Control: max-age=1');
    header ('Expires: Mon, 26 Jul 1997 05:00:00 GMT'); // Date in the past
    header ('Last-Modified: '.gmdate('D, d M Y H:i:s').' GMT'); // always modified
    header ('Cache-Control: cache, must-revalidate'); // HTTP/1.1
    header ('Pragma: public'); // HTTP/1.0
    $objwriter = \PHPExcel_IOFactory::createWriter($phpexcel, 'Excel5');
    $objwriter->save('php://output');
    exit;
}