我这里写了一个验证类，是通过文件头来判断文件格式.(也不是百分之百安全，如果用户伪造了文件头，也能通过验证)
代码如下:
<?php
/**
* 检证文件类型类
*
* @author Silver
*/
class FileTypeValidation
{
// 文件类型，不同的头信息
private static $_fileFormats = Array(
'jp2' => '0000000C6A502020',<br/> '3gp' => '0000002066747970',
'3gp5' => '0000001866747970',
'm4a' => '00000020667479704D3441',
'ico' => '00000100',
'spl' => '00000100',
'vob' => '000001BA',
'cur' => '00000200',
'wb2' => '00000200',
'wk1' => '0000020006040600',
'wk3' => '00001A0000100400',
'wk4' => '00001A0002100400',
'wk5' => '00001A0002100400',
'123' => '00001A00051004',
'qxd' => '00004D4D585052',
'mdf' => '010F0000',
'tr1' => '0110',
'rgb' => '01DA01010003',
'drw' => '07',
'dss' => '02647373',
'dat' => 'A90D000000000000',
'db3' => '03',
'qph' => '03000000',
'adx' => '80000020031204',
'db4' => '04',
'n' => 'FFFE0000',
'a' => 'FFFE0000',
'skf' => '07534B46',
'dtd' => '0764743264647464',
'db' => 'D0CF11E0A1B11AE1',
'pcx' => '0A050101',
'mp' => '0CED',
'doc' => 'D0CF11E0A1B11AE1',
'nri' => '0E4E65726F49534F',
'wks' => 'FF00020004040554',
'pf' => '1100000053434341',
'ntf' => '4E49544630',
'nsf' => '4E45534D1A01',
'arc' => '41724301',
'pak' => '5041434B',
'eth' => '1A350100',
'mkv' => '1A45DFA393428288',
'ws' => '1D7D',
'gz' => '1F8B08',
'tar.z' => '1FA0',
'ain' => '2112',
'lib' => '213C617263683E0A',
'msi' => 'D0CF11E0A1B11AE1',
'vmdk' => '4B444D',
'dsp' => '23204D6963726F73',
'amr' => '2321414D52',
'hdr' => '49536328',
'sav' => '24464C3240282329',
'eps' => 'C5D0D3C6',
'pdf' => '25504446',
'fdf' => '25504446',
'hqx' => '2854686973206669',
'log' => '2A2A2A2020496E73',
'ivr' => '2E524543',
'rm' => '2E524D46',
'rmvb' => '2E524D46',
'ra' => '2E7261FD00',
'au' => '646E732E',
'cat' => '30',
'evt' => '300000004C664C65',
'asf' => '3026B2758E66CF11',
'wma' => '3026B2758E66CF11',
'wmv' => '3026B2758E66CF11',
'wri' => 'BE000000AB',
'7z' => '377ABCAF271C',
'psd' => '38425053',
'sle' => '414376',
'asx' => '3C',
'xdr' => '3C',
'dci' => '3C21646F63747970',
'manifest' => '3C3F786D6C2076657273696F6E3D',
'xml' => '3C3F786D6C2076657273696F6E3D22312E30223F3E',
'msc' => 'D0CF11E0A1B11AE1',
'fm' => '3C4D616B65724669',
'mif' => '56657273696F6E20',
'gid' => '4C4E0200',
'hlp' => '4C4E0200',
'dwg' => '41433130',
'syw' => '414D594F',
'abi' => '414F4C494E444558',
'aby' => '414F4C4442',
