Carring data across redirect requests

1. Redirecting with URL templates

@RequestMapping(value = "save") 
public String saveDutyRelation(HttpServletRequest request, DutyRelation dutyRelation, Model model) throws Exception {
        try {
                requireNonNull(dutyRelation.getId(), "ID不能为空");
                requireNonNull(dutyRelation.getDutyCode(), "职务编码不能为空");
                dutyRelationService.updateById(dutyRelation, dutyRelation.getId());

                result.setMessageSuccess("保存成功");
        } catch (BusinessException e) {
            result.setCode(e.getCode());
            result.setMessage(e.getMessage());
        }
        model.addAttribute("username", dutyRelation.getId());
        model.addAttribute("id", dutyRelation.getId());
        model.addAttribute("code", dutyRelation.getDutyCode());

        return "redirect:/dutyRelation/{username}";
}

重定向的地址是：http://**/dutyRealtion/username?id=某个值&code=某个值

2. Working with flash attrbutes

@RequestMapping(value = "save") 
public String saveDutyRelation(HttpServletRequest request, DutyRelation dutyRelation, RedirectAttributes attributes) throws Exception {
        result = new Result();
        try {
                requireNonNull(dutyRelation.getId(), "ID不能为空");
                requireNonNull(dutyRelation.getDutyCode(), "职务编码不能为空");
                dutyRelationService.updateById(dutyRelation, dutyRelation.getId());

                result.setMessageSuccess("保存成功");
        } catch (BusinessException e) {
            result.setCode(e.getCode());
            result.setMessage(e.getMessage());
        }

        attributes.addAttribute("username",  dutyRelation.getId());
        attributes.addFlashAttribute(dutyRelation); // 可以根据类型推断 key 是 “dutyRelation”

        return "redirect:/dutyRelation/{username}";
}

原理：Flash attrbutes are stored in the session and then retrieved into the modal, surviving a redirect