注意：要把php.ini中 extension=php_mbstring.dll 前的;号去掉，重启apache就可以了。

我创建三个文件：text1.txt   text2.txt   text3.txt

分别以ASCII  UTF-8  UNICODE 的编码方式保存

 

<?php

define ('UTF32_BIG_ENDIAN_BOM',  chr(0x00) . chr(0x00) . chr(0xFE) . chr(0xFF));

define ('UTF32_LITTLE_ENDIAN_BOM',  chr(0xFF) . chr(0xFE) . chr(0x00) . chr(0x00));

define ('UTF16_BIG_ENDIAN_BOM',  chr(0xFE) . chr(0xFF));

define ('UTF16_LITTLE_ENDIAN_BOM', chr(0xFF) . chr(0xFE));

define ('UTF8_BOM',  chr(0xEF) . chr(0xBB) . chr(0xBF));

function detect_utf_encoding($text) {

    $first2 = substr($text, 0, 2);

    $first3 = substr($text, 0, 3);

    $first4 = substr($text, 0, 3);

   

    if ($first3 == UTF8_BOM) return 'UTF-8';

    elseif ($first4 == UTF32_BIG_ENDIAN_BOM) return 'UTF-32BE';

    elseif ($first4 == UTF32_LITTLE_ENDIAN_BOM) return 'UTF-32LE';

    elseif ($first2 == UTF16_BIG_ENDIAN_BOM) return 'UTF-16BE';

    elseif ($first2 == UTF16_LITTLE_ENDIAN_BOM) return 'UTF-16LE';

}

function getFileEncoding($str){

    $encoding=mb_detect_encoding($str);

    if(empty($encoding)){

        $encoding=detect_utf_encoding($str);

    }

    return $encoding;

}

$file = 'text1.txt';

echo getFileEncoding(file_get_contents($file));  // 输出ASCII

echo '<br />';

$file = 'text2.txt';

echo getFileEncoding(file_get_contents($file));  // 输出UTF-8

echo '<br />';

$file = 'text3.txt';

echo getFileEncoding(file_get_contents($file));  // 输出UTF-16LE

echo '<br />';

?>