Php 如何通过codeigniter导出和下载excel文件，excel文件未创建（下载）

headerCache控制：无存储，无缓存，必须重新验证

头痛控制：后检查=0，前检查=0，假

HeaderFragma：无缓存

标题“Content-Type:application/vnd.openxmlformats officedocument.spreadsheetml.sheet”

标题的内容处理：附件；filename=subscribers_sheet.csv'

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$objWriter->savephp://output;

日志中有错误吗？请在您的答案中添加一些上下文，并解释它如何解决OP的问题。就目前的情况而言，几行没有解释的代码并不是特别有用。

//query fetching data from database
if (!$query)
            return false; //if there is no data in query return false
            // Starting the PHPExcel library
            $this->load->library('PHPExcel');//loading library
            $objPHPExcel = new PHPExcel();
            $objPHPExcel->getProperties()->setTitle("export")->setDescription("none");

            $objPHPExcel->setActiveSheetIndex(0);

            // Field names in the first row
            $fields = $query->list_fields();
            $col = 0;
    //add data into cells
            foreach ($fields as $field) {
                $objPHPExcel->getActiveSheet()->setCellValueByColumnAndRow($col, 1, $field);
                $col++;
            }

            // Fetching the table data
            $row = 2;
            foreach ($query->result() as $data) {
                $col = 0;
                foreach ($fields as $field) {
                    $objPHPExcel->getActiveSheet()->setCellValueByColumnAndRow($col, $row, $data->$field);
                    $col++;
                }
                $row++;
            }

            $objPHPExcel->setActiveSheetIndex(0);

            $objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'csv');
    //creating excel sheet
            header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
            header('Content-Disposition: attachment;filename="subscribers_sheet.csv"');
            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->save('php://output');// inserting data into excel sheet