php 生成xml文件汉字中文编码问题

function array2xml($array, $xml = false){  
    if($xml === false){  
        $xml = new SimpleXMLElement('<root/>');  
    }  
    foreach($array as $key => $value){  
        if(is_array($value)){  
            array2xml($value, $xml->addChild($key));  
        }else{  
            $xml->addChild($key, $value);  
        }  
    }  
    return $xml->asXML();  
}  
 
header('Content-type: text/xml');  
print array2xml($array);

/*  
php 数组转换成xml  
*/ 
   
function array2xml($array, $xml = false){  
    if($xml === false){  
        $xml = new SimpleXMLElement('<root/>');  
    }  
    foreach($array as $key => $value){  
        if(is_array($value)){  
            array2xml($value, $xml->addChild($key));  
        }else{  
            //$value=utf8_encode($value);  
   
            if (preg_match("/([x81-xfe][x40-xfe])/", $value, $match)) {  
                $value = iconv('gbk', 'utf-8', $value);   //判断是否有汉字出现  
            }  
            $xml->addChild($key, $value);  
        }  
    }  
    return $xml->asXML();  
}