5.2、读取session

/**
 * 读取session
 * @param  String $name  session name
 * @return Mixed
 */
function get_session($name){
    if(isset($_SESSION[$name])){
        if($_SESSION[$name]['expire']>time()){
            return $_SESSION[$name]['data'];
        }else{
            self::clear_session($name);
        }
    }
    return false;
}