Check Using JSTL regarding Spring Binding Error - spring-mvc

Question

I have been trying this for a while but can't find the right solution.
I want to use JSTL to check if there is any binding errors (field error or global error) that happened in my Spring MVC 2.5.
I know I can use this code:
<p>
<spring:hasBindErrors name="searchItems">
An Error has occured
</spring:hasBindErrors>
</p>
But I want to utilize JSTL to check for any errors.
I have tried this one using JSTL:
<c:if test="${not empty errors}">
An Error has occured
</c:if>
But it seems that I cannot catch it correctly.
I need to used JSTL since there are other parts of the JSP that relies on the presence or absence of a binding errors.

Answer 1

As said
I want to utilize JSTL to check for any errors
Just use (It just works on Spring MVC 2.5 - Not portable for Spring MVC 3.0 although i suppose it is requestScope['bindingResult.<COMMAND_NAME_GOES_HERE>.allErrors'])
<c:if test="${not empty requestScope['org.springframework.validation.BindingResult.<COMMAND_NAME_GOES_HERE>'].allErrors}">
An Error has occured!!!
</c:if>
Keep in mind default command name is The non-qualified command class name with The first letter lowercased. Notice bellow command name is pet
private PetValidator petValidator = new PetValidator();
#RequestMapping(method.RequestMethod.POST)
public void form(Pet command, BindingResult bindingResult) {
if(petValidator.validate(command, bindingResult)) {
// something goes wrong
} else {
// ok, go ahead
}
}
So your form should looks like
<!--Spring MVC 3.0 form Taglib-->
<form:form modelAttribute="pet">
</form:form>
<!--Spring MVC 2.5 form Taglib-->
<form:form commandName="pet">
</form:form>
Unless you use #ModelAttribute
#RequestMapping(method.RequestMethod.POST)
public void form(#ModelAttribute("command") Pet command, BindingResult bindingResult) {
// same approach shown above
}
This way, your form should looks like
<!--Spring MVC 3.0 form Taglib-->
<form:form modelAttribute="command">
</form:form>
<!--Spring MVC 2.5 form Taglib-->
<form:form commandName="command">
</form:form>

Answer 2

Something like this:
<spring:hasBindErrors name="userName">
<c:set var="userNameHasError" value="true" />
</spring:hasBindErrors>
<c:choose>
<c:when test="${userNameHasError}">
<%-- Display username as textbox --%>
</c:when>
<c:otherwise>
<%-- Display username as label --%>
</c:otherwise>
</c:choose>
You can probably also put a setup the errors to catch all errors on the page (untested):
<spring:hasBindErrors name="*">
<c:set var="userNameHasError" value="true" />
</spring:hasBindErrors>
Enjoy!

Answer 3

After playing around with <spring:hasBindErrors> tag, I found it had certain limitations:
It is useful only when there are errors.
org.springframework.validation.Errors object is only accessible inside the tag
What if just wanted to know if there are errors or not. If there are no errors, <spring:hasBindErrors> is rendered useless. After doing some research with my colleague, we printed out all the request attributes. Turns out there is an attribute called:
org.springframework.validation.BindingResult.command
The command object here is your form backing command object.
As unintuitive as it may be named, this attribute holds a reference to our Errors object.
Thus, this works:
${requestScope['org.springframework.validation.BindingResult.command'].errorCount}
and gives us a handle over the much sought after Errors object in JSTL