Spring MVC重定向传参数

@RequestMapping(value = "answerAdd")
public String answerAdd(RedirectAttributes model, HttpServletRequest request, HttpServletResponse response){

try {
String ids = request.getParameter("ids");
model.addFlashAttribute("ids", ids);//get请求但参数不可见
ResponseMap responseMap=questionAnswerListService.save(RequestMap.init(request),"2",ids);
}catch (Exception e){
e.printStackTrace();
}

return "redirect:/questionAnswer/questionAnswerListDetails";
}

@RequestMapping(value="questionAnswerListDetails")
public String questionAnswerListDetails(Model model, HttpServletRequest request, HttpServletResponse response){
//前台获取的ID
String ids = request.getParameter("ids");
//重定向过来的ID
Map<String, Object> paramMap = model.asMap();
String id = (String)paramMap.get("ids");
if(!"".equals(id)&&id!=null){
ids=id;
}
}