clearstatcache();
        $_SESSION = ‘‘;
        $_COOKIE = ‘‘;
        //获得参数 signature nonce token timestamp echostr
        $nonce     = $_GET[‘nonce‘];
        $token     = ‘6699ssszzz‘;
        $timestamp = $_GET[‘timestamp‘];
        $echostr   = $_GET[‘echostr‘];
        $signature = $_GET[‘signature‘];
        //形成数组，然后按字典序排序
        $array = array();
        $array = array($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;
        }