tp5导出scv，支持百万导出

　　

    public function csv()
	{
			$title = 'cnepss';
			$headArr = ['qikan_id'=>'id','qikan_title'=>'标题','qc_name'=>'分类'];
			$this->exportCommon($title,$headArr,$conduct);
	}
/**
	* 导出
	* @param $title 导出的标题
	* @param $headArr 导出内容表头
	* @param $exportData 导出数据内容
	* @createTime:18-5-10 上午10:46
	* @author:lvqiang
	*/
	public function exportCommon($title, $headArr, $exportData)
	{
		$total = count($exportData);
		header("Content-type:application/vnd.ms-excel");
		header("Content-Disposition:filename=" . iconv("UTF-8", "GB18030", $title) . ".csv");
		$fp = fopen('php://output', 'a');
		$headName = array_keys($headArr);
		$headValue = array_values($headArr);
		fputcsv($fp, $headValue);
		$size = 2000;
		$groupNum = ceil($total / $size);
		for ($i = 0; $i <= $groupNum; $i++) {
		$exportDataTemp = array_slice($exportData, $size * $i, $size);
		foreach ($exportDataTemp as $item) {
			$rows = array();
			foreach ($headName as $name) {
				$rows[] = $item[$name];
			}
			// die;
			fputcsv($fp, $rows);
		}
		ob_flush();
		flush();
		}
		die;
	}