java - 如何在 JSP View 中显示实现的自定义 validator 的错误消息？

Question

我正在编写一个自定义 validator 。它应该只比较表单中的 2 个字段值，如果相同则拒绝。它成功拒绝，但我无法将错误消息发送到 View 。

这是我的自定义 validator 类:

public class CheckSameNameValidator implements Validator {

    @Override
    public boolean supports(Class<?> clazz) {
        // TODO Auto-generated method stub
        return FormModel.class.equals(clazz);
    }

    @Override
    public void validate(Object target, Errors errors) {
        FormModel model = (FormModel) target;
        if (model.getPerson1().getName().equals(model.getPerson2().getName())) {
            System.out.println("error occurred");
            errors.reject("person can not relate to himself!");
        }
    }

}

这是验证中使用的 FormModel 类:

public class FormModel {
    private Person person1;
    private Person person2;

    public Person getPerson1() {
        return person1;
    }

    public void setPerson1(Person person1) {
        this.person1 = person1;
    }

    public Person getPerson2() {
        return person2;
    }

    public void setPerson2(Person person2) {
        this.person2 = person2;
    }
}

这是使用的 Controller 方法:

@RequestMapping(value = "/setRelative", method = RequestMethod.POST)
    public ModelAndView setRelative(@Valid @ModelAttribute("people") FormModel people, BindingResult bindingResult,
            HttpServletRequest request) {
        logger.info("set relative controller");
        CheckSameNameValidator validator = new CheckSameNameValidator();
        validator.validate(people, bindingResult);
        if (bindingResult.hasErrors()) {
            ModelAndView model = new ModelAndView();
            model.setViewName("index");
            model.addObject("people", people);
            return model;
        } else {
  }
}

这是jsp中的形式:

<f:form class="form-inline" action="setRelative"
    modelAttribute="people">

    <label>Person:</label>
    <f:select cssStyle="width:150px" path="person1.name" items="${nameList}"
            multiple="false">
        </f:select> 
        <f:errors path="person1.name" class="alert alert-danger"></f:errors>

    <f:label path="person2.name">Relative:</f:label>
    <f:select cssStyle="width:150px" path="person2.name" items="${nameList}"
            multiple="false">
        </f:select> 
        <f:errors path="person2.name" class="alert alert-danger"></f:errors>

        <label>Person's Relation to Relative:</label>
    <f:select cssStyle="width:150px" path="person2.relations"
        items="${relationList}" multiple="false"> 
    </f:select>
    <button class="btn btn-primary" type="submit">Set
        relative</button>

</f:form>

如果发生错误，我希望将错误消息打印到 View 中。如何实现？

Answer 1

您可以在 Controller 中添加此消息model.addObject("message", "your error message");然后，将 jsp ${message} 放入您想要显示的位置。

这是在jsp中打印消息的另一种选择。希望对您有所帮助。