php中用file_get_contents函数获取带BOM的utf-8文件内容

$dataStr = file_get_contents("C:UsersAdministratorDesktop\13.txt");//utf8文件

if (preg_match('/^xEFxBBxBF/', $dataStr)) {//x表示16进制
    $dataStr = substr($dataStr, 3);//把文件的BOM头过滤
}

echo $dataStr ;

$encode = mb_detect_encoding($dataStr, array("ASCII","UTF-8","GB2312","GBK","BIG5"));//判断内容的字符编码

echo $encode;

if($encode == "UTF-8"){
    $dataStr = iconv("UTF-8","GBK",$dataStr);//把utf8编码转为GBK
}

echo $dataStr ;

参： https://www.cnblogs.com/hf8051/p/4600329.html