微信开发模式-微信接入验证代码中，<?php?>是什么意思？

1. wechatCallbackapiTest
   {

      public function valid()
      {
          $echoStr = $_GET["echostr"];
   
          //valid signature , option
          if($this->checkSignature()){
              echo $echoStr;
              exit;
          }
      }
   
      public function responseMsg()
      {
          //get post data, May be due to the different environments
          $postStr = $GLOBALS["HTTP_RAW_POST_DATA"];
   
            //extract post data
          if (!empty($postStr)){
                  /* libxml_disable_entity_loader is to prevent XML eXternal Entity Injection,
                     the best way is to check the validity of xml by yourself */
                  libxml_disable_entity_loader(true);
                    $postObj = simplexml_load_string($postStr, 'SimpleXMLElement', LIBXML_NOCDATA);
                  $fromUsername = $postObj->FromUserName;
                  $toUsername = $postObj->ToUserName;
                  $keyword = trim($postObj->Content);
                  $time = time();
                  $textTpl = "
                              
                              
                              %s
                              
                              
                              0
                              ";             
                  if(!empty( $keyword ))
                  {
                        $msgType = "text";
                      $contentStr = "Welcome to wechat world!";
                      $resultStr = sprintf($textTpl, $fromUsername, $toUsername, $time, $msgType, $contentStr);
                      echo $resultStr;
                  }else{
                      echo "Input something...";
                  }
   
          }else {
              echo "";
              exit;
          }
      }
          
      private function checkSignature()
      {
          // you must define TOKEN by yourself
          if (!defined("TOKEN")) {
              throw new Exception('TOKEN is not defined!');
          }
          
          $signature = $_GET["signature"];
          $timestamp = $_GET["timestamp"];
          $nonce = $_GET["nonce"];
                  
          $token = TOKEN;
          $tmpArr = array($token, $timestamp, $nonce);
          // use SORT_STRING rule
          sort($tmpArr, SORT_STRING);
          $tmpStr = implode( $tmpArr );
          $tmpStr = sha1( $tmpStr );
          
          if( $tmpStr == $signature ){
              return true;
          }else{
              return false;
          }
      }

   }

   ?>

帅哥||美女

看到你的疑惑，我也感觉很困惑，我有一个不成熟的小建议...在了解并且准备使用一门语言之前，大致浏览下它的官方手册。

点击此处查看手册链接

多看看手册，对使用PHP处理事务很有帮助的，个人认为，使用任何语言的时候都要先看一遍官方手册才行啊。

不知道是不是我对你的问题理解有问题，但从你问题和代码来看，这是代表这是PHP脚本

?> <<--php代码结束