nbkhope

// Given the controller
class DemoController {
    def hello() {
        render "greetings!"
    }
    
    def greet() {
        redirect action: 'hello'
    }
}

nbkhope

// In your controller, use the following code

// Single file
def file = request.getFile("identifier_name_in_html_tag_attribute")

// Useful information
file.empty
file.class  // => class org.springframework.web.multipart.support.StandardMultipartHttpServletRequest$StandardMultipartFile
file.name  // the name attribute value you used above (comes from html input tag)
file.originalFilename