php动态导出Excel大文件

<?php
/**
 * 生成excel文件操作
 *
 * @author wesley wu
 * @date 2013.12.9
 */
class Excel
{
	
	private $limit = 10000;
	
	public function download($fileName, $data)
	{
		$fileName = $this->_charset($fileName);
		header("Content-Type: application/vnd.ms-excel; charset=gbk");
		header("Content-Disposition: inline; filename=\"" . $fileName . ".xls\"");
		echo "<?xml version=\"1.0\" encoding=\"gbk\"?>\n
			<Workbook xmlns=\"urn:schemas-microsoft-com:office:spreadsheet\"
			xmlns:x=\"urn:schemas-microsoft-com:office:excel\"
			xmlns:ss=\"urn:schemas-microsoft-com:office:spreadsheet\"
			xmlns:html=\"http://www.w3.org/TR/REC-html40\">";
		echo "\n<Worksheet ss:Name=\"" . $fileName . "\">\n<Table>\n";
		$guard = 0;
		foreach($data as $v)
		{
			$guard++;
			if($guard==$this->limit)
			{
				ob_flush();
				flush();
				$guard = 0;
			}
			echo $this->_addRow($this->_charset($v));
		}
		echo "</Table>\n</Worksheet>\n</Workbook>";
	}
	
	private function _addRow($row)
	{
		$cells = "";
		foreach ($row as $k => $v)
		{
			$cells .= "<Cell><Data ss:Type=\"String\">" . $v . "</Data></Cell>\n"; 
		}
        return "<Row>\n" . $cells . "</Row>\n";
	}
	
	private function _charset($data)
	{
		if(!$data)
		{
			return false;
		}
		if(is_array($data))
		{
			foreach($data as $k=>$v)
			{
				$data[$k] = $this->_charset($v);
			}
			return $data;
		}
		return iconv('utf-8', 'gbk', $data);
	}
	
}

$excel = new Excel();
$data = array(
	array('数据1','数据2','数据3','数据4','数据5','数据6','数据7'),
	array('数据1','数据2','数据3','数据4','数据5','数据6','数据7'),
	array('数据1','数据2','数据3','数据4','数据5','数据6','数据7'),
	array('数据1','数据2','数据3','数据4','数据5','数据6','数据7'),
	array('数据1','数据2','数据3','数据4','数据5','数据6','数据7')
);
$excel->download('这是一个测试', $data);
?>