How to validate a MultipartFile using HibernateValidator?
hibernate, hibernate-validator, multipartform-data, spring, validation
Solution
Now I understand what you are trying to accomplish specifically. Well you could implement your own custom validation. For example, instead of implementing the Spring validator interface, implement a Hibernate `ConstraintValidator`, for a specific annotation that you define for this specific case. Check this link. In this case you could add an implementation for a `@NotNull` validator for a `MultipartFile` object.
Problem
I have a field of type `MultipartFile` in a backing bean which is bound to a Spring form (I'm using `MultipartFilter`), ``` <form:form htmlEscape="false" action="${pageContext.request.contextPath}/admin_side/Category.htm" id="dataForm" name="dataForm" method="post" commandName="categoryBean" enctype="multipart/form-data"> <input type="file" id="txtCatImage" name="txtCatImage"/> </form:form> ``` Backing Bean, ``` final public class CategoryBean { private MultipartFile txtCatImage=null; public MultipartFile getTxtCatImage() { return txtCatImage; } public void setTxtCatImage(MultipartFile txtCatImage) { this.txtCatImage = txtCatImage; } } ``` I have tried to apply annotations like `@NotEmpty` but didn't work. They ended up with an exception. javax.validation.UnexpectedTypeException: No validator could be found for type: org.springframework.web.multipart.MultipartFile I'm using Validation-API 1.0.0. Is this possible to perform a validation, if a user doesn't upload a file and press a submit button using HibernateValidator?