java - Spring 表格未在提交表格时重新填写

Question

当我加载此表单时，国家/地区表是从包含 240 个国家/地区的数据库中填充的。如果我提交它并带有一些空的必填字段，页面将再次重新加载并显示错误消息。但我没有列出任何国家。我使用相同的代码来填充 GET 和 POST 方法上的列表 - 见下文

      <form:form commandName="student_personal_info" method="post">
               <table>
                        <tr>
                        <td><form:label path="country">Country:</form:label></td>
                        <td><form:select path="country">
                            <form:option value="NONE" label=" --Select-- "></form:option>
                            <form:options items="${countries}"/>
                            </form:select>
                        </td>
            </tr></table>
        </form:form>



@RequestMapping(value = "student_personal_info", method = RequestMethod.GET)
    public ModelAndView DisplayPersonalForm(ModelAndView model) {
        StudentPersonalInfo personalInfo = new StudentPersonalInfo();
        model.addObject("student_personal_info", personalInfo);

        model.addObject("countries",getCountries());
        return model;
    }  //this works fine

    @RequestMapping(value = "student_personal_info", method = RequestMethod.POST)
    public String PersonalFormSubmitted(
            @ModelAttribute("student_personal_info") @Valid StudentPersonalInfo student_personal_info,
            BindingResult result, ModelAndView model) {
        model.addObject("countries", getCountries());
        if (result.hasErrors()) {
            logger.info("From student personal info, there are "
                    + String.valueOf(this.getCountries().size())
                    + "  Countries"); //This prints 240 countries on the consule
            return "student_personal_info";
        }

        else
            return "redirect:/display_program_of_study.tsegay";
    }

我的所有其他配置都工作正常

Answer 1

我猜你无法在不返回的情况下填充ModelAndView，因此你需要使用另一种参数类型:

@RequestMapping(value = "student_personal_info", method = RequestMethod.POST)        
public String PersonalFormSubmitted(
         @ModelAttribute("student_personal_info") @Valid StudentPersonalInfo student_personal_info,
         BindingResult result, ModelMap model) { ... }