header('Content-type:text/html;charset=utf-8'); 
/** 
* 可以統(tǒng)計(jì)中文字符串長度的函數(shù) 
* @param $str 要計(jì)算長度的字符串 
* @param $type 計(jì)算長度類型，0(默認(rèn))表示一個(gè)中文算一個(gè)字符，1表示一個(gè)中文算兩個(gè)字符 
* 
*/ 
function abslength($str) 
{ 
if(empty($str)){ 
return 0; 
} 
if(function_exists('mb_strlen')){ 
return mb_strlen($str,'utf-8'); 
} 
else { 
preg_match_all("/./u", $str, $ar); 
return count($ar[0]); 
} 
} 
$str = '我們都是中國人啊，ye！'; 
$len = abslength($str); 
var_dump($len); //return 12 
$len = abslength($str,'1'); 
echo '<br />'.$len; //return 22 
/* 
utf-8編碼下截取中文字符串,參數(shù)可以參照substr函數(shù) 
@param $str 要進(jìn)行截取的字符串 
@param $start 要進(jìn)行截取的開始位置，負(fù)數(shù)為反向截取 
@param $end 要進(jìn)行截取的長度 
*/ 
function utf8_substr($str,$start=0) { 
if(empty($str)){ 
return false; 
} 
if (function_exists('mb_substr')){ 
if(func_num_args() >= 3) { 
$end = func_get_arg(2); 
return mb_substr($str,$start,$end,'utf-8'); 
} 
else { 
mb_internal_encoding("UTF-8"); 
return mb_substr($str,$start); 
} 
} 
else { 
$null = ""; 
preg_match_all("/./u", $str, $ar); 
if(func_num_args() >= 3) { 
$end = func_get_arg(2); 
return join($null, array_slice($ar[0],$start,$end)); 
} 
else { 
return join($null, array_slice($ar[0],$start)); 
} 
} 
} 
$str2 = 'wo要截取zhongwen'; 
echo '<br />'; 
echo utf8_substr($str2,0,-4); //return wo要截取zhon

<?php
/* 
* 中文截取，支持gb2312,gbk,utf-8,big5 
* 
* @param string $str 要截取的字串 
* @param int $start 截取起始位置 
* @param int $length 截取長度 
* @param string $charset utf-8|gb2312|gbk|big5 編碼 
* @param $suffix 是否加尾綴 
*/ 
public function csubstr($str, $start=0, $length, $charset="utf-8", $suffix=true) 
{ 
if(function_exists("mb_substr")) 
{ 
if(mb_strlen($str, $charset) <= $length) return $str; 
$slice = mb_substr($str, $start, $length, $charset); 
} 
else 
{ 
$re['utf-8'] = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|[\xe0-\xef][\x80-\xbf]{2}|[\xf0-\xff][\x80-\xbf]{3}/"; 
$re['gb2312'] = "/[\x01-\x7f]|[\xb0-\xf7][\xa0-\xfe]/"; 
$re['gbk'] = "/[\x01-\x7f]|[\x81-\xfe][\x40-\xfe]/"; 
$re['big5'] = "/[\x01-\x7f]|[\x81-\xfe]([\x40-\x7e]|\xa1-\xfe])/"; 
preg_match_all($re[$charset], $str, $match); 
if(count($match[0]) <= $length) return $str; 
$slice = join("",array_slice($match[0], $start, $length)); 
} 
if($suffix) return $slice."…"; 
return $slice; 
}