How should I store an object in Spring MVC to use in multiple pages?

[Sai Subramanyam]

I am creating a shopping cart application to learn Spring MVC. I want to display list of all categories(ex:Mobiles,Books,Stationery,Movies) and subcategories(Ex:iPhone,Motorola under Mobiles) in more than one page. i.e; Home Page, Products page, Category page.

I want to display this category and subcategories list in the header of my application so that I can use these in all the pages.(like below image)



In the Home Page controller I am retrieving the list of categories,subcategories and featured products and passing them to the home page.

@Controller
public class CatalogController {

    @Autowired
    private CategoryConfigService categoryConfigurationService;
    @Autowired
    private ProductConfigService productConfigurationService;
    private static final Logger logger = LoggerFactory
            .getLogger(CatalogController.class);

    /**
     * Catalog Controller method which retrieves the information required in the
     * application home page(Categories,SubCategories)
     * 
     * @return Home Page View
     */
    @RequestMapping(value = "/home", method = RequestMethod.GET)
    public String returnHomePage(Model model) {
        logger.info("Processing information for home page");
        List<Category> categoriesList = categoryConfigurationService
                .getAllCategories();
        Map<Category, List<SubCategory>> categoryMap = new HashMap<Category, List<SubCategory>>();
        for (Category category : categoriesList) {
            List<SubCategory> subCategoryList = categoryConfigurationService
                    .getAllSubCategoriesByCategoryId(category.getId());
            categoryMap.put(category, subCategoryList);
        }
        model.addAttribute("categoryMap", categoryMap);
        model.addAttribute("featProd",
                productConfigurationService.getFeaturedProducts());

        return "home";
    }


}

I have 2 questions:

1.How can I store the object categoryMap in Spring to access it in multiple pages??


2. I have done the same project using JSP and Servlets and I have stored the categoryMap in application scope so that I can use it in multiple pages. Is this a right approach ? If not how can I do this in a better way ?

Please help!! Thanks

[Mohamed Sanaulla]

You can create a reusable fragment and include that in all your pages.

That reusable fragment would fetch the categories and sub categories and cache it locally for sometime and refresh the cache on demand.