Spring 两个对象的表单验证

Question

Spring 启动应用程序遇到了一个复杂的问题，我已经尝试解决了一段时间，希望有人能帮助我。我已经删除了项目的所有其他部分，并试图使其尽可能简单。如果您转到 localhost:8080，将会出现一个表单，其中有两个文本框供您输入两个姓名，还有一个提交按钮。第一个姓名将存储在 Nominee 对象中，第二个姓名将存储在 Submitter 对象中。当您单击提交时，它将对字段执行验证以确保它们都不为空。我将 post 下面的代码并在最后解释我的问题。

Application.java

@SpringBootApplication
@EnableJms
@EnableWebMvc
public class Application {

    public static void main(String[] args) throws Exception {
        // Launch the application
        SpringApplication.run(Application.class, args);
    }
}

WebController.java

@Controller
public class WebController extends WebMvcConfigurerAdapter {
    protected static final Logger LOG = LoggerFactory.getLogger(WebController.class);

    @InitBinder("nominee")
    protected void initNomineeBinder(WebDataBinder binder) {
        binder.setValidator(new NomineeValidator());
    }

    @InitBinder("submitter")
    protected void initSubmitterBinder(WebDataBinder binder) {
        binder.setValidator(new SubmitterValidator());
    }

    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/success").setViewName("success");
    }

    @RequestMapping(value="/", method=RequestMethod.GET)
    public String showForm(Model model) {
        model.addAttribute("nominee", new Nominee());
        model.addAttribute("submitter", new Submitter());
        return "form";
    }

    @RequestMapping(value="/", method=RequestMethod.POST)
    public String checkPersonInfo(@ModelAttribute(value="nominee") @Valid Nominee nominee,
                                  @ModelAttribute(value="submitter") @Valid Submitter submitter,
                                  BindingResult bindingResult, @Valid Model model) {
        LOG.info("Nominee to string: " + nominee.toString());
        LOG.info("Submitter to string: " + submitter.toString());
        LOG.info("bindingResult to string: " + bindingResult.toString());
        if (bindingResult.hasErrors()) {
            return "form";
        }

        return "redirect:/success";
    }
}

Nominee.java

import lombok.Data;

@Data
public class Nominee {
    private String name;
}

NomineeValidatior.java

public class NomineeValidator implements Validator {

    public boolean supports(Class clazz) {
        return Nominee.class.equals(clazz);
    }

    public void validate(Object object, Errors errors) {
        ValidationUtils.rejectIfEmpty(errors, "name", "name", "This field is empty.");
    }
}

Submitter.java

import lombok.Data;

@Data
public class Submitter {
    private String sname;
}

SubmitterValidator.java

public class SubmitterValidator implements Validator {

    public boolean supports(Class clazz) {
        return Submitter.class.equals(clazz);
    }

    public void validate(Object object, Errors errors) {
        ValidationUtils.rejectIfEmpty(errors, "sname", "sname", "This field is empty.");
    }
}

form.html

<html>
<body>
<form role="form" th:action="@{/}" method="post">
    <h2>Nominee details</h2>
    <table>
        <tr>
            <td>Name:</td>
            <td>
                <input type="text" th:field="${nominee.name}"/>
            </td>
            <td><p th:if="${#fields.hasErrors('nominee.name')}" th:errors="${nominee.name}">Empty field</p></td>
        </tr>
    </table>
    <h2>Your details</h2>
    <table>
        <tr>
            <td>Your name:</td>
            <td>
                <input type="text" th:field="${submitter.sname}"/>
            </td>
            <td><p th:if="${#fields.hasErrors('submitter.sname')}" th:errors="${submitter.sname}">Empty field</p></td>
        </tr>
    </table>
    <div>
        <button type="submit">Submit nomination</button>
    </div>
</form>
</body>
</html>

success.html

<html><body>Form successfully submitted.</body></html>

如果我将第一个文本字段留空（并填写或不填写第二个文本字段），屏幕上会显示一条错误消息：

Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback. Tue May 12 13:10:17 AEST 2015 There was an unexpected error (type=Bad Request, status=400). Validation failed for object='nominee'. Error count: 1

我不知道如何修复它，使第一个文本框留空不会导致白色标签错误页面。如果我将第二个文本字段留空但填写第一个文本字段，它的行为完全正常，所以我不确定如果我以相反的方式尝试它为什么会导致错误。任何解决此问题的帮助将不胜感激。

此外，您可能已经注意到我必须使用 'name' 和 'sname' 作为我在 Nominee 和 Submitter 中的变量，如果我将它们都设置为 'name' 那么它不会好好工作。如果有任何方法可以编辑它以便他们都可以使用 'name'，我很想知道如何。

编辑：找到了解决方案。在 WebController 中，checkPersonInfo 需要为每个被验证的对象提供一个单独的 BindingResult。 BindingResult 需要紧跟在每个@Valid 对象之后的方法参数中。

所以，在 WebController.java 中，这个：

@RequestMapping(value="/", method=RequestMethod.POST)
public String checkPersonInfo(@ModelAttribute(value="nominee") @Valid Nominee nominee,
                              @ModelAttribute(value="submitter") @Valid Submitter submitter,
                              BindingResult bindingResult, @Valid Model model) {
    LOG.info("Nominee to string: " + nominee.toString());
    LOG.info("Submitter to string: " + submitter.toString());
    LOG.info("bindingResult to string: " + bindingResult.toString());
    if (bindingResult.hasErrors()) {
        return "form";
    }

    return "redirect:/success";
}

需要变成这样：

@RequestMapping(value="/", method=RequestMethod.POST)
public String checkPersonInfo(@ModelAttribute(value="nominee") @Valid Nominee nominee,
                              BindingResult bindingResultNominee,
                              @ModelAttribute(value="submitter") @Valid Submitter submitter,
                              BindingResult bindingResultSubmitter) {
    LOG.info("Nominee to string: " + nominee.toString());
    LOG.info("Submitter to string: " + submitter.toString());
    if (bindingResultNominee.hasErrors() || bindingResultSubmitter.hasErrors()) {
        return "form";
    }

    return "redirect:/success";
}

（模型对象已被删除，因为它实际上从未在任何地方使用过，如果您需要使用 @Valid 验证它，那么您将添加第三个 BindingResult 对象。）

Answer 1

通常的情况是使用 Dto 对象。这意味着您创建一个包含所有相关表单字段的对象并基于该对象进行验证。

例如：

@Data
public class MyDto {

    private Nominee nominee;

    private Submitter submitter;
}

@RequestMapping(value="/", method=RequestMethod.POST)
public String checkPersonInfo(@Valid MyDto dto, BindingResult bindingResult) {
    LOG.info("Nominee to string: " + dto.getNominee().toString());
    LOG.info("Submitter to string: " + dto.getSubmitter().toString());
    LOG.info("bindingResult to string: " + bindingResult.toString());
    if (bindingResult.hasErrors()) {
        return "form";
    }
    return "redirect:/success";
}

此外，您可以将类似的东西添加到您的控制器中。

@ExceptionHandler(Throwable.class)
public ModelAndView processError(Throwable ex) {
    ex.toString();
    // do something and return a ModelAndView object as you like.
}

Answer 2

找到解决办法。在 WebController 中，checkPersonInfo 需要为每个被验证的对象提供一个单独的 BindingResult。 BindingResult 需要紧跟在每个@Valid 对象之后的方法参数中。

因此，在 WebController.java 中，这：

    @RequestMapping(value="/", method=RequestMethod.POST)
public String checkPersonInfo(@ModelAttribute(value="nominee") @Valid Nominee nominee,
                              @ModelAttribute(value="submitter") @Valid Submitter submitter,
                              BindingResult bindingResult, @Valid Model model) {
    LOG.info("Nominee to string: " + nominee.toString());
    LOG.info("Submitter to string: " + submitter.toString());
    LOG.info("bindingResult to string: " + bindingResult.toString());
    if (bindingResult.hasErrors()) {
        return "form";
    }

    return "redirect:/success";
}

需要变成这样：

    @RequestMapping(value="/", method=RequestMethod.POST)
public String checkPersonInfo(@ModelAttribute(value="nominee") @Valid Nominee nominee,
                              BindingResult bindingResultNominee,
                              @ModelAttribute(value="submitter") @Valid Submitter submitter,
                              BindingResult bindingResultSubmitter) {
    LOG.info("Nominee to string: " + nominee.toString());
    LOG.info("Submitter to string: " + submitter.toString());
    if (bindingResultNominee.hasErrors() || bindingResultSubmitter.hasErrors()) {
        return "form";
    }

    return "redirect:/success";
}

（模型对象已被删除，因为它实际上从未在任何地方使用过，如果您需要使用 @Valid 验证它，那么您将添加第三个 BindingResult 对象。）

Spring 两个对象的表单验证

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