RouteInfoManager#pickupTopicRouteData的调用方法

public RemotingCommand getRouteInfoByTopic(ChannelHandlerContext ctx,
                                           RemotingCommand request) throws RemotingCommandException {
    ......
  //这块代码就是上面解析的代码，获取到topicRouteData对象
    TopicRouteData topicRouteData = this.namesrvController.getRouteInfoManager().pickupTopicRouteData(requestHeader.getTopic());
​
    if (topicRouteData != null) {
        //判断nameserver的orderMessageEnable配置是否打开
        if (this.namesrvController.getNamesrvConfig().isOrderMessageEnable()) {
            //如果配置打开了，根据namespace和topic名字获取kvConfig配置文件中顺序消息配置内容
            String orderTopicConf =
                this.namesrvController.getKvConfigManager().getKVConfig(NamesrvUtil.NAMESPACE_ORDER_TOPIC_CONFIG,
                                                                        requestHeader.getTopic());
            //封装orderTopicConf
            topicRouteData.setOrderTopicConf(orderTopicConf);
        }
​
        byte[] content = topicRouteData.encode();
        response.setBody(content);
        response.setCode(ResponseCode.SUCCESS);
        response.setRemark(null);
        return response;
    }
  //如果没有获取到topic路由，那么reponseCode为TOPIC_NOT_EXIST
    response.setCode(ResponseCode.TOPIC_NOT_EXIST);
    response.setRemark("No topic route info in name server for the topic: " + requestHeader.getTopic()
                       + FAQUrl.suggestTodo(FAQUrl.APPLY_TOPIC_URL));
    return response;
}