最初在网上直接找的代码，在项目中用了之后发现存在汉字中存在数字和特殊字符的时候乱码，下面这段代码转为unicode是好用的，转utf-8好没测试。 

/** 
     * utf-8 转unicode 
     * 
     * @param string $name 
     * @return string 
     */  
    function utf8_unicode($name){  
        $name = iconv('UTF-8', 'UCS-2', $name);  
        $len  = strlen($name);  
        $str  = '';  
        for ($i = 0; $i < $len - 1; $i = $i + 2){  
            $c  = $name[$i];  
            $c2 = $name[$i + 1];  
            if (ord($c) > 0){   //两个字节的文字  
                $str .= '\u'.base_convert(ord($c), 10, 16).str_pad(base_convert(ord($c2), 10, 16), 2, 0, STR_PAD_LEFT);  
                //$str .= base_convert(ord($c), 10, 16).str_pad(base_convert(ord($c2), 10, 16), 2, 0, STR_PAD_LEFT);  
            } else {  
                $str .= '\u'.str_pad(base_convert(ord($c2), 10, 16), 4, 0, STR_PAD_LEFT);  
                //$str .= str_pad(base_convert(ord($c2), 10, 16), 4, 0, STR_PAD_LEFT);  
            }  
        }  
        $str = strtoupper($str);//转换为大写  
        return $str;  
    }  
  
    /** 
     * unicode 转 utf-8 
     * 
     * @param string $name 
     * @return string 
     */  
    function unicode_decode($name)  
    {  
        $name = strtolower($name);  
        // 转换编码，将Unicode编码转换成可以浏览的utf-8编码  
        $pattern = '/([\w]+)|(\\\u([\w]{4}))/i';  
        preg_match_all($pattern, $name, $matches);  
        if (!empty($matches))  
        {  
            $name = '';  
            for ($j = 0; $j < count($matches[0]); $j++)  
            {  
                $str = $matches[0][$j];  
                if (strpos($str, '\\u') === 0)  
                {  
                    $code = base_convert(substr($str, 2, 2), 16, 10);  
                    $code2 = base_convert(substr($str, 4), 16, 10);  
                    $c = chr($code).chr($code2);  
                    $c = iconv('UCS-2', 'UTF-8', $c);  
                    $name .= $c;  
                }  
                else  
                {  
                    $name .= $str;  
                }  
            }  
        }  
        return $name;  
    }  

/** 
     * utf-8 转unicode 
     * 
     * @param string $name 
     * @return string 
     */  
    function utf8_unicode($name){  
        $name = iconv('UTF-8', 'UCS-2', $name);  
        $len  = strlen($name);  
        $str  = '';  
        for ($i = 0; $i < $len - 1; $i = $i + 2){  
            $c  = $name[$i];  
            $c2 = $name[$i + 1];  
            if (ord($c) > 0){   //两个字节的文字  
                $str .= '\u'.base_convert(ord($c), 10, 16).str_pad(base_convert(ord($c2), 10, 16), 2, 0, STR_PAD_LEFT);  
                //$str .= base_convert(ord($c), 10, 16).str_pad(base_convert(ord($c2), 10, 16), 2, 0, STR_PAD_LEFT);  
            } else {  
                $str .= '\u'.str_pad(base_convert(ord($c2), 10, 16), 4, 0, STR_PAD_LEFT);  
                //$str .= str_pad(base_convert(ord($c2), 10, 16), 4, 0, STR_PAD_LEFT);  
            }  
        }  
        $str = strtoupper($str);//转换为大写  
        return $str;  
    }  
  
    /** 
     * unicode 转 utf-8 
     * 
     * @param string $name 
     * @return string 
     */  
    function unicode_decode($name)  
    {  
        $name = strtolower($name);  
        // 转换编码，将Unicode编码转换成可以浏览的utf-8编码  
        $pattern = '/([\w]+)|(\\\u([\w]{4}))/i';  
        preg_match_all($pattern, $name, $matches);  
        if (!empty($matches))  
        {  
            $name = '';  
            for ($j = 0; $j < count($matches[0]); $j++)  
            {  
                $str = $matches[0][$j];  
                if (strpos($str, '\\u') === 0)  
                {  
                    $code = base_convert(substr($str, 2, 2), 16, 10);  
                    $code2 = base_convert(substr($str, 4), 16, 10);  
                    $c = chr($code).chr($code2);  
                    $c = iconv('UCS-2', 'UTF-8', $c);  
                    $name .= $c;  
                }  
                else  
                {  
                    $name .= $str;  
                }  
            }  
        }  
        return $name;  
    }