PHP返回JSON和XML类

 <?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);