springmvc 用jsp取值的问题

代码如下:

@RequestMapping({"/","/index"})
    public String index(Model model) {
        //1.获取所有的首页栏目
        List<Channel> cs = channelService.listTopNavChannel();
        model.addAttribute("cs",cs);
        BaseInfo bi = BaseInfoUtil.getInstacne().read();
        int picNum = bi.getIndexPicNumber();
        model.addAttribute("shxw", topicService.listTopicByChannelAndNumber(10,14));
        model.addAttribute("ggl", topicService.listTopicByChannelAndNumber(13,8));
        model.addAttribute("xxkd", topicService.listTopicByChannelAndNumber(22,8));
        model.addAttribute("pics",indexPicService.listIndexPicByNum(picNum));
        model.addAttribute("shdt", listByParentNavAttachment(2));
        model.addAttribute("shhd",attachmentService.listChannelPic(11,4));
        model.addAttribute("shkh", attachmentService.listChannelPic(23,1));

        model.addAttribute("shky", listByParentNavAttachment(3));//图片
        model.addAttribute("yqlj", cmsLinkService.findByType(null).getDatas());
        model.addAttribute("baseInfo", BaseInfoUtil.getInstacne().read());
        return "index/index";
    }

    @RequestMapping("/topic/{tid}")
    public String showTopic(@PathVariable int tid,Model model) {
        model.addAttribute("topic", topicService.load(tid));
        List<Attachment> atts = attachmentService.listAttachByTopic(tid);
        if(atts.size()>0) {
            model.addAttribute("hasAtts", true);
            model.addAttribute("atts", atts);
        } else {
            model.addAttribute("hasAtts",false);
        }
        return "index/topic";
    }

如果我再index页面已经获取cs等index方法已经给model赋的值.那么当我从
index页面点击链接跳转到topic页面时,我如何获取原先在index方法已经赋值的值?
有几种办法?有没有优缺点

把对象放session里面session生命周期长，不太重要东西不要放session里面

为什么不把数据封装进javabean然后用@responsebody直接将javabean响应给页面，跳转的时候再将页面的数据封装进javabean传到mvc里面

可以用session,也可以把数据放在一个隐藏的输入框中，在方法上接收