/**
*ControllerA的代码
**/
@RequestMapping("addComment")
	public String addComment(Comment comment,Model model){
		if(cs.addComment(comment)){
			model.addAttribute("id",comment.getCommentBookId());
            //一定要加重定向
			return "redirect:getBookDetail.action";
		}
		return "fail.jsp";
	} 
/**
*ControllerB的代码
**/
@RequestMapping("getBookDetail")
	public String getBookDetail(Model model,@RequestParam(value="id",required=true)int id){
		Book book = bs.getBookById(id);
		model.addAttribute("book",book);
		return "bookDetail.jsp";
	}