Question

您必须使用控制器在jsp上显示错误消息

这是控制器的代码

@RequestMapping(value = "/addUrl", method = RequestMethod.POST)
public String addUrl(WebRequest request) {

    logger.info("Calling Add Filters in POST mode");

    String serverUrl = request.getParameter("serverUrl");
    logger.info("ServerUrl" + serverUrl);

    if(serverUrl!=null)
    {
        mongoService.setServerUrl(serverUrl);
    }
    else
    {
        //show message on UI if serverUrl is null

    }

    return "redirect:config.do";
}

很遗憾地说，但我对春天来说是全新的，所以不知道这样做？。提前感谢

Answer 1

使用ModelMap，

的对象

@RequestMapping(value = "/addUrl", method = RequestMethod.POST)
public String addUrl(WebRequest request,ModelMap map) {

    logger.info("Calling Add Filters in POST mode");

    String serverUrl = request.getParameter("serverUrl");
    logger.info("ServerUrl" + serverUrl);    
    if(serverUrl!=null)
    {
        mongoService.setServerUrl(serverUrl);
    }
    else
    {
       String errormsg="sorry un expected error has occured"
       map.put("errMsg",errormsg)
    }    
    return "redirect:config.do";
}

也可以使用

完成

redirectAttributes.addFlashAttribute("errMsg",errormsg);

redirectAttributes.addAttribute从您的属性中构造请求参数，并使用请求参数重定向到所需的页面

在你的jsp中，

可以使用EL ${errMsg}

访问

Answer 2

它在redirectAttributes上显示错误我想在用户输入密码错误

时在我的登录屏幕上显示错误消息

我的代码在下面给出; -

    @RequestMapping(value="/login", method= RequestMethod.POST)
public ModelAndView login(@RequestParam(value= "name") String name, @RequestParam(value= "password") String password,ModelMap m) throws SQLException{

    String uname= name;
    String pass= password; 


    Connection connection = (Connection) DriverManager.getConnection("jdbc:mysql://localhost:3306/sbank","root","root");
    Statement statement = (Statement) connection.createStatement();
    ResultSet resultSet = (ResultSet) statement.executeQuery("select * from account where name='"+uname+"' and password='"+password+"'");

    if(resultSet.next()){

        return new ModelAndView("home","command",resultSet);

    }
    else{

        String message="Sorry UserName Or Password Is Wrong";   
        ModelAndView model= new ModelAndView();
         redirectAttributes.addFlashAttribute("error", message);
         model.setViewName("redirect:/Index.jsp");
            return model;
    }
}

Answer 3

您可以使用RedirectAttributes，如下所示：

@RequestMapping(value = "/failure")
    public ModelAndView loginFailure(final RedirectAttributes redirectAttributes) {
        String message = "Invalid username or password!";
        ModelAndView model = new ModelAndView();
        redirectAttributes.addFlashAttribute("error", message);
        // model.addObject("error",message);
        model.setViewName("redirect:/login");
        return model;
    }

在视图中，您只需将其显示如下：

<c:if test="${not empty error}">
        <div class="alert alert-danger"><c:out value="${error}"/></div>
</c:if>

希望这个帮助

使用控制器在jsp上显示错误消息

3 个答案: