前端程式碼：

  <div class="col-lg-3">
                <input id="in-oldWebsite" type="text" name="oldWebsite" value="${oldWebsite}" class="sp-supInfo-input" placeholder="" readonly>
   </div>

後端程式碼：

@RequestMapping("/webAddress")
public String webAddressHttpServletRequest request, HttpServletResponse response )
{
ModelAndView modelAndView = new ModelAndView();

String oldWebsite = "www.dyssb.com";

modelAndView.addObject("oldWebsite", oldWebsite);

return "/Update/webAddress";
}

發現前端取不到值。

根據後端向前端傳值的三種方法改正如下：

法一 ：

@RequestMapping("/webAddress")
public String webAddress(HttpServletRequest request, HttpServletResponse response )
{

String oldWebsite = "www.dyssb.com";

request.setAttribute("oldWebsite", oldWebsite);

return "/Update/webAddress";

}

法二：

@RequestMapping("/webAddress")
public ModelAndView webAddress( HttpServletRequest request, HttpServletResponse response )
{
ModelAndView modelAndView = new ModelAndView();
 
String oldWebsite = "www.dyssb.com";

modelAndView.addObject("oldWebsite", oldWebsite);
modelAndView.setViewName("/Update/webAddress");

return modelAndView;
}

法三：

@RequestMapping("/webAddress")
public String webAddress(Model model,HttpServletRequest request, HttpServletResponse response )
{

String oldWebsite = "www.dyddb.com";

model.addAttribute("oldWebsite",oldWebsite);

return "/Update/webAddress";

}

本文感謝大牛指點。

新手，有不當之處或更好地方法請指教。