public function utf8_unicode($str) {    $unicode = array();    $values = array();    $lookingFor = 1;    for ($i = 0; $i < strlen( $str ); $i++ ) {        $thisValue = ord( $str[ $i ] );        if ( $thisValue < ord('A') ) {            // exclude 0-9            if ($thisValue >= ord('0') && $thisValue <= ord('9')) {                 // number                 $unicode[] = chr($thisValue);            }            else {                 $unicode[] = '%'.dechex($thisValue);            }        } else {            if ( $thisValue < 128) {                $unicode[] = $str[ $i ];            } else {                if ( count( $values ) == 0 ) {                    $lookingFor = ( $thisValue < 224 ) ? 2 : 3;                }                $values[] = $thisValue;                if ( count( $values ) == $lookingFor ) {                    $number = ( $lookingFor == 3 ) ?                        ( ( $values[0] % 16 ) * 4096 ) + ( ( $values[1] % 64 ) * 64 ) + ( $values[2] % 64 ):                        ( ( $values[0] % 32 ) * 64 ) + ( $values[1] % 64 );                    $number = dechex($number);                    $unicode[] = (strlen($number)==3)?"\u0".$number:"\u".$number;                    $values = array();                    $lookingFor = 1;                } // if            } // if        }    } // for    return implode("",$unicode);}

参考文章：http://randomchaos.com/documents/?source=php_and_unicode