PHP 生成JSON问题

<code>PHP</code><code>function json_encode_wrapper ($result)
{
    if(defined('JSON_UNESCAPED_UNICODE')){
        return json_encode($result,JSON_UNESCAPED_UNICODE|JSON_NUMERIC_CHECK);
    }else {
        return preg_replace(
            array("#\\\u([0-9a-f][0-9a-f][0-9a-f][0-9a-f])#ie", "/\"(\d+)\"/",),
            array("iconv('UCS-2', 'UTF-8', pack('H4', '\\1'))", "\\1"),
            json_encode($result)
        );
    }
}
</code>

<code>echo json_encode($arr, JSON_UNESCAPED_UNICODE);
</code>