本文实例讲述了php通过文件头判断格式的方法。分享给大家供大家参考，具体如下：
function judgeFile($file,$form){if(!empty($file) && !empty($form)){$filehead = fopen($file,'r');$bin = fread($filehead, 2);fclose($filehead);$data = unpack('C2chars', $bin);$type_code = intval($data['chars1'].$data['chars2']);switch ($type_code) {case 7790: $fileType = 'exe';break; case 7784: $fileType = 'midi';break; case 8075: $fileType = 'zip';break; case 8297: $fileType = 'rar';break; case 255216: $fileType = 'jpg';break; case 7173: $fileType = 'gif';break; case 6677: $fileType = 'bmp';break; case 13780: $fileType = 'png';break; default: $fileType = 'unknown';break;}if(!is_array($form)){if($fileType==$form){return true;}else{return false;}}else{if(in_array($file, $form)){return true;}else{return FALSE;}}}else{return false;}} 
