Spring portlet mvc Validation fails during submission of the editted form - spring

Question

I have a form with few validations on it.
During new form submission, if validation fails I can see those error messages.
but, during editing the form when I change the field to blank intentionally and submit the form error messages are not shown on Jsp page but I can get the errorcount in controller as 1 .
<portlet:actionURL var="actionUrl">
<portlet:param name="action" value="editCommunity"/>
<portlet:param name="communityID" value="${community.id}"/>
</portlet:actionURL>
<liferay-ui:tabs names="Details" />
<form:form commandName="community" method="post" action="${actionUrl}">
<form:hidden path="id"/>
<div><form:errors cssClass="portlet-msg-error" path="*"/></div>
<table class="manager-detail">
<tr>
<th class="portlet-form-field-label">
<label for="community_label_name"><spring:message code="community.label.name"/></label>
<span class="manager-field-required">*</span>
</th>
<td><form:input id="community_label_name" cssClass="portlet-form-input-field" path="name" size="30" maxlength="80" /></td>
</tr>
My edit controller method.....
rendering edit form
#RequestMapping(params = "action=editCommunity")
public String showEditCommunityForm(final RenderRequest request,
#RequestParam(value="communityID") Long id, final Model model)
throws CommunityNotFoundException {
final ThemeDisplay themeDisplay = (ThemeDisplay) request
.getAttribute(WebKeys.THEME_DISPLAY);
model.addAttribute("community", communityService.getCommunity(id));
return "communityEdit";
}
edited form is submitted
#RequestMapping(params = "action=editCommunity")
public void submitEditCommunityForm(final ActionRequest request,
final ActionResponse response,
#ModelAttribute("community") Community community,
BindingResult result, Model model) throws SystemException, PortalException {
communityValidator.validate(community, result);
if (result.hasErrors()) {
System.out.println("validation errors size..."+result.getErrorCount());
//model.addAttribute("community", community);
response.setRenderParameter("action", "editCommunity");
response.setRenderParameter("communityID", String.valueOf(community
.getId()));
}
}
It is not full code but a block
I have tried couple of things like,
changing the http method from post to POST, but nothing works. Validation perfectly works during form creation, but not during edit.
Am I missing anything? please give me suggestions.
Cheers
Vamshi

Answer 1

Preserving the validation error messages can be a real pain!
I have tried a lot of things - from configuring the redirect behavior of the portlet container to using jsr303 instead of spring validation.
The only solution I have consistently had and success implementing is really ugly:
Do the validation in an action method.
If errors are encountered save the BindingResult/Errors-object with "your own key" in the Spring model and interrupt the action handling.
You are redirected to the render method
There you pick up the Errors-object and put it back to the key where "Spring validation" expects it.
In code this looks something like this:
#ActionMapping
public void invite(#ModelAttribute MyFormBean myFormBean,
BindingResult result, Model model) {
// validate indata
myValidator.validate(myFormBean, result);
// Workaround to preserve Spring validation errors
if (result.hasErrors()) {
model.addAttribute("errors", result);
return;
}
...
}
#RequestMapping
public String showForm(#ModelAttribute("myFormBean") MyFormBean myFormBean,
Model model) {
...
// Workaround to get the errors form-validation from actionrequest
Errors errors = (Errors) model.asMap().get("errors");
if (errors != null) {
model.addAttribute(
"org.springframework.validation.BindingResult.myFormBean", errors);
}
return "myForm";
}
The information stored in the Model under "org.springframework.validation.BindingResult.*" are deleted automatically between the action processing and the render processing, and by preserving it explicitly in "errors" the information will be available to the view.
This is an ugly solution, you have to know more than you want about how the implementation really works, it is counter intuitive and if not properly commented this code could easily be removed by someone not familiar with the problem, but it is not a lot of code and it works.

Answer 2

You can omit the #ModelAttribute in the render phase and retrieve it from the model:
#ActionMapping
public void invite(#ModelAttribute MyFormBean myFormBean,
BindingResult result, Model model) {
// validate indata
myValidator.validate(myFormBean, result);
...
}
#RequestMapping
public String showForm(Model model) {
MyFormBean myFormBean = (MyFormBean)model.asMap().get("myFormBean");
...
return "myForm";
}