Spring - How to ignore/reset some error(s) in BindingResult? - spring-mvc

Question

Having this handler method:
#RequestMapping(method = RequestMethod.POST, value = "/myform1")
public String formPost(#ModelAttribute("myModel") #Valid MyModel myModel, BindingResult binder)
how can I ignore errors on certain (or all) fields?
Even if I omit the #Valid annotation, it still detects errors like "abc entered into a Number field" (ie binder.hasErrors() returns true). And the the error message (from the catalog) is displayed on the final web page, which I do not want.
If I omit the BindingResult binder, then the code never reaches this method but throws an exception/error before it.
Is there a #DontValidateAtAll annotation or some other method to achieve this?
Related problem: I can not override the bad value in the method, it keeps showing the old rejected value. For example, user enters "abc" into myModel.someNumber and submits the form, then even if I do myModel.setSomeNumber(22) in the method formPost(), after returning from it, the web page (JSP) will show "abc" (and the error text) instead of 22 in that field.

Answer 1

For the specific String-to-Number conversion exception you were referring to, you can use the below manipulation. This is a type conversion exception that occurs even before Spring MVC's form validation, ie, even before the validate() method.
If your only purpose is to NOT see the errors on your final web page, then you can write extra code in your Controller method.
#RequestMapping(method = RequestMethod.POST, value = "/myform1")
public ModelAndView formPost(#ModelAttribute("myModel") #Valid MyModel myModel, BindingResult binder){
List<ObjectError> errors = bindingResult.getAllErrors();
boolean hasIgnorableErrorsOnly = true;
if(bindingResult.hasErrors()){
for(ObjectError error : errors){
if(error.getCode().equals("myModel.someNumber.NotANumber")){ //or whatever your error code is
}else{
hasIgnorableErrorsOnly = false;
}
}
}
if(hasIgnorableErrorsOnly){
//You have not shown where your final view is. I am assuming your myModel form view is myform.jsp and final web page is myModel.jsp
// Notice that I have also changed this method signature to return ModelAndView instead of only String view.
if(myModel.getSomeNumber() == null)
myModel.setSomeNumber(22);
return new ModelAndView("myModel.jsp", myModel); //Take care of view Resolvers here
}else{
return new ModelAndView("myform.jsp", myModel); //Take care of view Resolvers here
}
}
Now, if your BindingResult has more than ignorable errors, then it would go to myModel.jsp and I believe you already have code in place for display of errors. But if, because of above code, you are forwarded to myModel.jsp, you would have to iterate over the ${errors} key on your jsp and write the someNumber element so that it does not show errors. For example,
<spring:hasBindErrors name="myModel">
<c:forEach items="${errors.allErrors}" var="error">
<c:if test="${error.code eq 'myModel.someNumber.NotANumber'}">
//skip your display of global errors
</c:if>
</c:forEach>
</spring:hasBindErrors>

Answer 2

This works:
add a (Model)Map parameter to the handler method (it is usually used anyway, I omitted it in the question for brevity)
overwrite the model attribute with a fresh copy
Code:
#RequestMapping(method = RequestMethod.POST, value = "/myform1")
public String formPost(#ModelAttribute("myModel") #Valid MyModel myModel, BindingResult binder, Map<String, Object> modmap) {
if(ignore_errors) {
modmap.put("myModel", new MyModel());
return "myForm.jsp";
} // else ... other things
}
Apparently this procedure makes the framework to "forget" about the validation errors.
Note: I use Spring 3.0.x, other versions might behave differently.