回答

mb_substr支持中文截取，代码如下：

<?php

/**
 * 字符串截取，支持中文
 * @param $str
 * @param int $start
 * @param $length
 * @param string $charset
 * @param bool $suffix
 * @return false|string
 * @author 肆月
 */
function msubstr($str, $start = 0, $length, $charset = "utf-8", $suffix = true)
{
    if (function_exists("mb_substr")) {
        if ($suffix) {
            if (strlen($str) > $length)
                return mb_substr($str, $start, $length, $charset) . "...";
            else
                return mb_substr($str, $start, $length, $charset);
        } else {
            return mb_substr($str, $start, $length, $charset);
        }
    } elseif (function_exists('iconv_substr')) {
        if ($suffix) {
            return iconv_substr($str, $start, $length, $charset);
        } else {
            return iconv_substr($str, $start, $length, $charset);
        }
    }
}


echo msubstr("bfw技术社区",0,4);