php如何导出excel表格？

public function exportExcel()
{
    //先获取数据
    $where['comid'] = session('uid');
    $res = M('cheliang')->where($where)->select();
   // var_dump($res);die;

    //下面就是导出的步骤了
    vendor('PHPExcel0.Classes.PHPExcel');

    $objPHPExcel = new \PHPExcel();
    $objPHPExcel->createSheet(0);
    $objPHPExcel->setActiveSheetIndex(0);
   //只需要把你想要的字段改成你自己需要的就可以了！！！
        $objPHPExcel->setActiveSheetIndex(0)
            ->setCellValue('A1', '考试人')
            ->setCellValue('B1', '车牌')
            ->setCellValue('C1', '考试时间')
            ->setCellValue('D1', '考试分数')
            ->setCellValue('E1', '签名');

        $objPHPExcel->getActiveSheet()->getColumnDimension('B')->setWidth(20);//设置单元格宽度
        $objPHPExcel->getActiveSheet()->getColumnDimension('C')->setWidth(50);//设置单元格宽度
        $objPHPExcel->getActiveSheet()->getColumnDimension('D')->setWidth(20);//设置单元格宽度
        $objPHPExcel->getActiveSheet()->getColumnDimension('E')->setWidth(20);//设置单元格宽度
        $objPHPExcel->getActiveSheet()->getStyle('A1')->getFont()->setBold(true);      //第一行是否加粗
        $objPHPExcel->getActiveSheet()->getStyle('B1')->getFont()->setBold(true);      //第一行是否加粗
        $objPHPExcel->getActiveSheet()->getStyle('C1')->getFont()->setBold(true);      //第一行是否加粗
        $objPHPExcel->getActiveSheet()->getStyle('D1')->getFont()->setBold(true);      //第一行是否加粗
        $objPHPExcel->getActiveSheet()->getStyle('E1')->getFont()->setBold(true);      //第一行是否加粗
        //$objPHPExcel->getActiveSheet()->getStyle('A1')->getFont()->setSize(16);         //第一行字体大小
        // 设置垂直居中
        $objPHPExcel->getActiveSheet()->getStyle('A1')->getAlignment()->setVertical(\PHPExcel_Style_Alignment::VERTICAL_CENTER);
        $objPHPExcel->getActiveSheet()->getStyle('B1')->getAlignment()->setVertical(\PHPExcel_Style_Alignment::VERTICAL_CENTER);
        $objPHPExcel->getActiveSheet()->getStyle('C1')->getAlignment()->setVertical(\PHPExcel_Style_Alignment::VERTICAL_CENTER);
        $objPHPExcel->getActiveSheet()->getStyle('D1')->getAlignment()->setVertical(\PHPExcel_Style_Alignment::VERTICAL_CENTER);
        $objPHPExcel->getActiveSheet()->getStyle('E1')->getAlignment()->setVertical(\PHPExcel_Style_Alignment::VERTICAL_CENTER);

        // 设置行高度
        $objPHPExcel->getActiveSheet()->getDefaultRowDimension()->setRowHeight(20); //设置默认行高
        $objPHPExcel->getActiveSheet()->getRowDimension('1')->setRowHeight(30);    //第一行行高
        //循环添加数据，注意的是下面的$kk+2，是因为$kk是下标，从0开始的，而第一行是你的标题，所以要从第二行开始才是你的数据
        foreach ($data as $kk => $vv) {
            $no = $kk + 2;
                $currentSheet = $objPHPExcel->getActiveSheet();
                $currentSheet->setCellValue('A' . $no, $vv['xueyuan']['name']);
                $currentSheet->setCellValue('B' . $no, $vv['xueyuan']['chepaihao']);
                $currentSheet->setCellValue('C' . $no, date('Y-m-d H:i:s',$vv['addtime']).'至'.date('Y-m-d H:i:s',$vv['sbttime']));
                $currentSheet->setCellValue('D' . $no, $vv['score']);
                //设置单元格高度，这个是重点哦
                $currentSheet->getRowDimension($no) -> setRowHeight(40);
                // 图片生成
                $objDrawing[$kk] = new \PHPExcel_Worksheet_Drawing();//这个就是生成图片的类（重点）
                $objDrawing[$kk]->setPath('./'.$vv['qmimg']);/图片的路径
                // 设置宽度高度
                $objDrawing[$kk]->setHeight(85);//照片高度
                $objDrawing[$kk]->setWidth(100); //照片宽度
                /*设置图片要插入的单元格*/
                $objDrawing[$kk]->setCoordinates('E'.$no);
                // 图片偏移距离
                 $objDrawing[$kk]->setOffsetX(12);
                 $objDrawing[$kk]->setOffsetY(12);
                $objDrawing[$kk]->setWorksheet($objPHPExcel->getActiveSheet());
        }

    $objPHPExcel->setActiveSheetIndex(0);
    header('Content-Type: application/vnd.ms-excel');

    header('Content-Disposition: attachment;filename="' . '文件名称'. '.xls"');
    header('Cache-Control: max-age=0');
    $objWriter = \PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel5');
    $objWriter->save('php://output');
    exit;
}