Spring：重定向属性未添加到模型中

Question

我有通过两个句柄重定向到视图的场景，在第一个句柄中我使用了@RedirectAttribute并使用了它的方法addFlashAttribute。 如果我的属性值（String）没有空格或特殊字符，但是空格和特殊字符不起作用，这可以正常工作。

@RequestMapping(value="/addCategory")
public String addCategory(@ModelAttribute("category") Category category ,
                    @RequestParam int access,RedirectAttributes redirectAttributes , Model model){
    System.out.println();
    if(categoryService.isCategoryExist(category).equals("category_not_exist")){
        categoryService.addCategory(category);
        //redirectAttributes.addAttribute("addedCategoryName", category.getCategoryName());
        System.out.println("isCategoryAdded YES " +category.getCategoryName().trim());
        System.out.println("Category Name  "+category.getCategoryName().trim());
        redirectAttributes.addFlashAttribute("isCategoryAdded", "yes");
        redirectAttributes.addFlashAttribute("addedCategoryName", category.getCategoryName().trim());
    }
    else{
        //redirectAttributes.addAttribute("existCategoryName", category.getCategoryName());
        System.out.println("isCategoryAdded NO ");
        System.out.println("Category Name  "+category.getCategoryName().trim());
        redirectAttributes.addFlashAttribute("isCategoryAdded", "no");
        redirectAttributes.addFlashAttribute("addedCategoryName", category.getCategoryName().trim());
    }
    System.out.println();
    System.out.println("addedCategoryName  *********  "+category.getCategoryName().trim());
    System.out.println();
    redirectAttributes.addAttribute("paramCategoryId", category.getCategoryId());
    redirectAttributes.addAttribute("paramCategoryName", category.getCategoryName());
    redirectAttributes.addAttribute("paramParentCategoryId", category.getParentCategoryId());
    redirectAttributes.addAttribute("paramMovement", "backward");
    redirectAttributes.addAttribute("parentCategoryId", category.getCategoryId());  
    redirectAttributes.addAttribute("access", access);  

    /*redirectAttributes.addAttribute("parentCategoryId", category.getParentCategoryId());*/
    return "redirect:/Category/categories";
}

在View JSP中

<c:choose>
    <c:when test="${ isCategoryAdded eq 'yes'}">
        <div class="successMessage">Category '${addedCategoryName }' added successfully.</div>
    </c:when>
    <c:when test="${ isCategoryAdded eq 'no'}">
        <div class="errorMessage">Category '${addedCategoryName }' already exist.</div>
    </c:when>
</c:choose>

仅当类别名称包含空格和特殊字符

时才会出现问题

如何解决？

谢谢。