原理主要是php代码生成excel文件，被输出内容以‘,’隔开，自动识别逗号符隔开的内容放入excel内不同的表格内，需要换行处加上转义符\n，输出内容涉及中文的需转化编码utf-8为gbk。
方式一：
header("Content-type:application/vnd.ms-excel");
header("Content-Disposition:p_w_upload;filename=pay-".time().".xls");
header('Pragma: no-cache');
header('Expires: 0');
foreach ($datas as $val) {
echo iconv('UTF-8','GBK//IGNORE',implode("\t",$val))."\n";
}方式二：
$str_list = '';
foreach($result as $k=>$v){
$str_list .= $arr[$k]['createtime'].",".$arr[$k]['sid'].",".iconv('utf-8','GBK',$arr[$k]['accountingtype']).",".iconv('utf-8','GBK', $arr[$k]['accountingitem']).",".iconv('utf-8','GBK',$arr[$k]['moneytype'])."," . iconv('utf-8','GBK',$arr[$k]['remark']) . "," . iconv('utf-8','GBK',$arr[$k]['accountingtype1']). "," .iconv('utf-8','GBK',$arr[$k]['balance']). ""."\n";
}
$bankcard = iconv('utf-8','GBK','时间'); //中文转码
$accountname = iconv('utf-8','GBK','商家id');
$money = iconv('utf-8','GBK','收/支');
$moenytype = iconv('utf-8','GBK','记账项目');
$bankname = iconv('utf-8','GBK','账户类型');
$bankbranch = iconv('utf-8','GBK','内容');
$provice = iconv('utf-8','GBK','发生金额');
$diqu = iconv('utf-8','GBK','账户余额');
$str = $bankcard.",".$accountname.",".$money.",".$moenytype.",".$bankname.",".$bankbranch.",".$provice.",".$diqu."\n";
$filename = date('YmdHis').'.csv';
$this->export_csv($filename,$str.$str_list);
