PHP实现返回JSON和XML的类分享

<?php
    class Reponse{
        //private $result = array(code=null,message=null,data=>null);
        /**
         * @desc 返回JSON格式
         * @param int $code
         * @param string $message
         * @param array  $data
         * return string
         */
        public static function json($code,$message = null,$data = array()){
            if(!is_numeric($code)){
                return false;
            }
            $result = array(
                code=>$code,
                message=>$message,
                data=>$data
            );
            return json_encode($result);
            exit;
        }
        /**
         * @desc 返回xml格式数据
         * @parma int $code 状态码
         * @param string $message 提示
         * @param array $data 数据
         * return string
         */
         public static function xml($code,$message = ,$data = array()){
            if(!is_numeric($code)){
                return false;
            }
            $result = array(
                code=>$code,
                message=>$message,
                data=>$data
            );
            $xml = ;
            $xml .= "<?xml version=1.0 encoding=UTF-8?>\n";
            $xml .= "<root>\n";
            $xml .= self::xmlEncode($result);
            $xml .= "</root>";
            header("Content-Type:text/xml");
            echo $xml;
         }
         public static function xmlEncode($result){
            $xml = $attr =;
            foreach($result as $key=>$val){
                if(is_numeric($key)){
                    $attr = "id={$key}";
                    $key = "item{$key}";
                }
                $xml .= "<{$key} {$attr}>";
                $xml .= is_array($val) ? self::xmlEncode($val) : $val;
                $xml .= "</{$key}>\n";
            }
            return $xml;
         }
    }
    $data = array(
        id=>1,
        age=>20,
        username=>tim,
        others=>array(1,2,3),
    );
    Reponse::xml(200,success,$data);
    Reponse::json(200,success,$data);