php怎么样把xls转换成csv ？如何实现Excel的xls和xlsx文件转换成c

PHPExcel完全可以满足你的要求，给个简单处理例子，具体的你还是看看PHPExcel的文档,代码如下:

$filename = "myexcel.xlsx";

$objReader = PHPExcel_IOFactory::createReader('Excel2007');

$objPHPExcel = $objReader->load($filename);

$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'CSV');

$objWriter->save(str_replace('.xlsx', '.csv',$filename));