The second step into the WeChat trap. How to apply for a second WeChat ID. How to change the WeChat account for the second time. Change WeChat for the second time.

<span style="font-family:Courier New;font-size:14px;"><?php
define("TOKEN","weixin");
$weixinObj = new Wechat();
$weixinObj->valid();

class Wechat{
	public function valid(){
		$echoStr = $_GET['echostr'];
		//如果是第一次接入
		if($this->checkSignature() && $echoStr ){
			echo $echoStr;
			exit;
		}else{
	    $this->responseMsg();
	   }
	}
	//校验方法
	private function checkSignature(){
		$signature = $_GET['signature'];
		$timestamp = $_GET['timestamp'];
		$nonce = $_GET['nonce'];
		$token = TOKEN;

		$tmpArr = array($token, $timestamp, $nonce);
		sort($tmpArr);
		$tmpStr = implode($tmpArr);
		$tmpStr = sha1($tmpStr);
		if($tmpStr == $signature){
			return true;
		}else{
			return false;
		}
	}
/* 普通文本消息
<xml>
 <ToUserName><![CDATA[toUser]]></ToUserName>
 <FromUserName><![CDATA[fromUser]]></FromUserName>
 <CreateTime>1348831860</CreateTime>
 <MsgType><![CDATA[text]]></MsgType>
 <Content><![CDATA[this is a test]]></Content>
 <MsgId>1234567890123456</MsgId>
 </xml>
*/
	public function responseMsg(){
	    //获取微信服务器POST请求中的数据
	    
	    $postStr = $GLOBALS["HTTP_RAW_POST_DATA"];
	    if( !empty($postStr) ){
            $postObj = simplexml_load_string($postStr, 'SimpleXMLElement', LIBXML_NOCDATA);	
            $fromUser = $postObj->FromUserName;
            $toUser = $postObj->ToUserName;
            $keyword = trim($postObj->Content);
            $time = time();
            
    	    $template = "<xml>
                         <ToUserName><![CDATA[%s]]></ToUserName>
                         <FromUserName><![CDATA[%s]]></FromUserName>
                         <CreateTime>%s</CreateTime>
                         <MsgType><![CDATA[%s]]></MsgType>
                         <Content><![CDATA[%s]]></Content>
                         </xml>";
    	    if( !empty($keyword) ){
    	        $msgType = 'text';
    	        $content = "谢谢您的关注";
    	        $info = sprintf($template, $fromUser, $toUser, $time, $msgType, $content);
    	        echo $info;
    	    }else{
    	        echo "请输入关键字";//消息为空
    	    }
    	}else{
    	    echo "";
    	    exit;
    	}
    }
}</span>