Spring boot - How to validate Multipartfile in rest application

Question

I want to validate extension of Multipartfile object. I added @Valid and my custon annotation to parameter @ImageFileValid but it doesn't work.

@PutMapping("/{id}")
ProductDto updateProduct(@RequestPart @Valid ProductDto product, @PathVariable Long id,@RequestPart @Valid @ImageFileValid MultipartFile image) {
    return productMapper.productToProductDto(productService.update(productMapper.productDtoToProduct(product),id));
}

Answer 1

Very short but clear reference from Spring-Boot, Validation:

The method validation feature supported by Bean Validation 1.1 is automatically enabled as long as a JSR-303 implementation (such as Hibernate validator) is on the classpath. This lets bean methods be annotated with javax.validation constraints on their parameters and/or on their return value. Target classes with such annotated methods need to be annotated with the @Validated annotation at the type level for their methods to be searched for inline constraint annotations.

So, please annotate (the containing) controller class with @Validated & report if any issues.

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A sample repo at github.