/**

     * 审核填写的URL

     */

    public function checkUrl(){

        //获得参数 signature nonce token timestamp echostr

        $nonce     = $_GET('nonce');

        $token     = 'sudi';

        $timestamp = $_GET('timestamp');

        $echostr   = $_GET('echostr');

        $signature = $_GET('signature');

        //形成数组，然后按字典序排序

        $array = array($nonce, $timestamp, $token);

        sort($array);

        //拼接成字符串,sha1加密 ，然后与signature进行校验

        $str = sha1( implode( $array ) );

        if( $str  == $signature && $echostr ){

            //第一次接入weixin api接口的时候

            echo  $echostr;

            exit;

        }else{

            $this->reponseMsg();

        }

    }