About @ModelAttribute, two commands, BindingResult [SPR-7358]

[spring-projects-issues]

kendy lau opened SPR-7358 and commented

How to deal with two @ModelAttribute(s) like the follows:

@RequestMapping(method = RequestMethod.POST)
public String processSubmit(@ModelAttribute("owner") Owner owner, @ModelAttribute("contact") Contact contact,
BindingResult result, SessionStatus status) {

	new OwnerValidator().validate(owner, result);	
	if (result.hasErrors()) {	
		return "owners/form";
	}	
	else {	
		this.clinic.storeOwner(owner);
		status.setComplete();
		return "redirect:/owners/" + owner.getId();
	}	
}		

When error occures during the OwnerValidator validate the command owner, the BingingResult don't know which command object is the errors binded for.

the validator is like this

public class OwnerValidator {

public void validate(Owner owner, Errors errors) {		
	if (!StringUtils.hasLength(owner.getFirstName())) {	
		errors.rejectValue("firstName", "required", "required");
	}	
	if (!StringUtils.hasLength(owner.getLastName())) {	
		errors.rejectValue("lastName", "required", "required");
	}	

.....

---

Affects: 3.0.2

Attachments:

• BUG_ModelAttribute.zip (163.42 kB)

Issue Links:

• Mention position of Errors instance in method signature more explicitly [SPR-7103] #11763 Mention position of Errors instance in method signature more explicitly
• BindingResult argument only resolved right after model attribute argument [SPR-4753] #9430 BindingResult argument only resolved right after model attribute argument

[spring-projects-issues]

Juergen Hoeller commented

Note that each model attribute is supposed to have its own BindingResult. We associate them by parameter order: A BindingResult always applies to the model attribute parameter right before it in the handler method's signature.

So in your case, you'd need to declare a method signature like the following:

public String processSubmit(@ModelAttribute("owner") Owner owner, BindingResult ownerResult, @ModelAttribute("contact") Contact contact, BindingResult contactResult, SessionStatus status)

We recently improved the documentation on this, so that relationship should hopefully be a bit more obvious now.

Juergen

[spring-projects-issues]

kendy lau commented

Oh! I see. Thank you very much!