Spring 2.5在验证器实现中发现表单验证错误don't update View < Form:error/

Question

作为参考，我一直在使用这个:http://www.mkyong.com/spring-mvc/spring-mvc-form-handling-example/

我有一个类叫做ejournalvalidator。java:

package com.blah.blah.validator;
import org.springframework.validation.Errors;
import org.springframework.validation.ValidationUtils;
import org.springframework.validation.Validator;
import com.blah.blah.EJournalForm;
public class EJournalValidator implements Validator{
    public boolean supports(Class clazz) {
        return EJournalForm.class.isAssignableFrom(clazz);
    }
    public void validate(Object target, Errors errors) {
        ValidationUtils.rejectIfEmptyOrWhitespace(errors, "strStartDate",
                "ejournal.strStartDate", "Field name is required.");
    }
}

它被映射到servlet.xml中的控制器，其中包含spring 2.5 bean列表中的一些重要方面:

<bean name="/app/eJournal.html" class="com.blah.blah.EJournalController">
    <property name="formView" value="/app/eJournal"/>
    <property name="validator">
        <bean class="com.blah.blah.EJournalValidator" />
    </property> 
</bean>
<bean name="/app/eJournalResult.html" class="com.blah.blah.EJournalResultController"></bean>
<bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
    <property name="basenames">
      <list>
        <value>/WEB-INF/messages/message</value>
      </list>
    </property>
</bean>
<bean id="localeResolver" class="org.springframework.web.servlet.i18n.SessionLocaleResolver"/>
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
    <property name="prefix" value="/WEB-INF/jsp/"/>
    <property name="suffix" value=".jsp"/>
</bean>

它验证我的表单中的搜索条件，由我们的model .java文件和一个用于表单加载和提交的控制器表示(对于我们来说是showForm()和handleRequest())。问题是，我的视图似乎没有得到更新，我的标签在我的。jsp:

<td><form:input id="strStartDate" path="strStartDate"/></td>
<td><form:errors path="strStartDate" cssClass="error" /></td>

不幸的是，即使我知道当我通过EJournalValidator.java文件中的断点为这个字段提交null时，错误被适当地标记，错误在视图中没有更新。知道这是为什么吗?有人说，如果你重定向使用:

return "redirect:/spring/person/list";

那么这可能会导致类似这样的事情，但这似乎不是这里的情况。

在调试中，如果我在EJournalValidator.java的验证方法中放置一个断点，并在我试图在检查的字段中提交空白时检查错误变量，则发现这些错误:

org.springframework.validation.BindException:beanpropertybindingresult: 1个错误字段'strStartDate'上对象'ej'中的字段错误:拒绝值[];代码[ejournal.strStartDate.ej.strStartDate, ejournal.strStartDate.strStartDate ejournal.strStartDate.java.lang.String ejournal.strStartDate);参数[];默认消息[字段名是必需的]

你知道为什么调试时发现的错误没有显示给用户吗?

Edit:添加Controller handleRequest方法，以防需要知道。

protected ModelAndView handleRequest(HttpServletRequest request,
        HttpServletResponse response, Object command, BindException errors)
        throws Exception {
    EJournalForm form = (EJournalForm) command;
    form.setUser(getUser());
    form.load(request, false);
    HttpSession session = request.getSession(false);
    session.setAttribute(LBIBOConstants.SESSION_VAR_TAB_ALERT_MSG, null);
    return new ModelAndView(getFormView(), getCommandName(), form);
}

Edit 2:添加来自SimpleFormController的片段，这似乎是它被卡住的。它永远不会击中我的控制器的handlerrequest()方法，除非当它检查这个时不存在错误:

protected ModelAndView processFormSubmission(
        HttpServletRequest request, HttpServletResponse response, Object command, BindException errors)
        throws Exception {
    if (errors.hasErrors()) {
        if (logger.isDebugEnabled()) {
            logger.debug("Data binding errors: " + errors.getErrorCount());
        }
        return showForm(request, response, errors);
    }
    else if (isFormChangeRequest(request, command)) {
        logger.debug("Detected form change request -> routing request to onFormChange");
        onFormChange(request, response, command, errors);
        return showForm(request, response, errors);
    }
    else {
        logger.debug("No errors -> processing submit");
        return onSubmit(request, response, command, errors);
    }
}

我还注意到……因为这个，我要重写我的控制器方法，但意识到我扩展SessionSimpleFormController，而不是SimpleFormController。现在看看为什么一个人会扩展一个或另一个，因为我首先基于别人的工作，然后注意到在我上面显示的链接中，他们正在使用SimpleFormController。

Answer 1

更改handleRequest方法，以便在验证期间发生错误时返回现有的表单/模型对象。当你返回new ModelAndView时，它会清除错误，因此你不会在视图中看到它们。尝试使用RedirectView重定向到相同的视图，而不会丢失绑定到表单/模型的错误，如:

    protected ModelAndView handleRequest(HttpServletRequest request,
            HttpServletResponse response, Object command, BindException errors)
            throws Exception {
        EJournalForm form = (EJournalForm) command;
        form.setUser(getUser());
        form.load(request, false);
        HttpSession session = request.getSession(false);
        session.setAttribute(LBIBOConstants.SESSION_VAR_TAB_ALERT_MSG, null);
        if(errors.hasErrors()){
            return new ModelAndView(new RedirectView(getFormView()));
        }else{
            return new ModelAndView("anotherView", "commandName", form);
        }   
    }

从Spring 3+开始，getFormView()和getCommandName()已弃用

Answer 2

我确实解决了这个问题，最后我已经开始使用SimpleFormController而不是SessionSimpleFormController，并改变了一些事情。

最后，它看起来像这样…但也许有一种方法可以让它与Session控制器一起工作。

public class EJournalController extends SimpleFormController {
public EJournalController() {
    setCommandClass(EJournalForm.class);
    setCommandName("ej"); 
}
@Override
protected ModelAndView showForm (HttpServletRequest request,
        HttpServletResponse response, BindException errors) throws Exception {
    Calendar cal = Calendar.getInstance();
    Calendar calMidnight= Calendar.getInstance();
    calMidnight.set(Calendar.HOUR_OF_DAY, 0);
    calMidnight.set(Calendar.MINUTE, 0);
    calMidnight.set(Calendar.SECOND, 0);
    HttpSession session = request.getSession(true);
    ModelAndView view = null;
    LocaleResolver localeResolver = RequestContextUtils.getLocaleResolver(request);
    localeResolver.setLocale(request, response, LocaleUtilities.getUsersLocale(session));
    EJournalForm form = new EJournalForm();
    view = new ModelAndView(getFormView(), getCommandName(), form);
    form.setStrStartDate(form.getSdfDate().format(cal.getTime()).toString());
    form.setStrEndDate(form.getSdfDate().format(cal.getTime()).toString());
    form.setStrStartTime(form.getSdfTime().format(calMidnight.getTime()).toString());
    form.setStrEndTime(form.getSdfTime().format(cal.getTime()).toString());
    return view;
}
protected ModelAndView handleRequest(HttpServletRequest request,
        HttpServletResponse response, Object command, BindException errors)
        throws Exception {
    EJournalForm form = (EJournalForm) command;
    if(errors.hasErrors()){
        return onSubmit(request, response, command, errors);
    }
    else{
        form.load(request, false);          
        HttpSession session = request.getSession(false);
        session.setAttribute(LBIBOConstants.SESSION_VAR_TAB_ALERT_MSG, null);
        return new ModelAndView("app/eJournal", "ej", form);
    }  
}
@Override
protected ModelAndView processFormSubmission(HttpServletRequest request, HttpServletResponse response, Object command, BindException errors) throws Exception {
        return handleRequest(request, response, command, errors);
}

}