delete an existing file in grails - grails

Question

I am saving image files in my web folder. But at the time of saving or suppose a user want to change his picture than i want to delete the old picture and save the new one with the same file name. But I am failing after trying. Can anyone please help me on this please? Here is all my action below :
my save action >>>
def savePicture = {
String message = ""
def user = User.findById(1)
def userId = user.id
MultipartHttpServletRequest mpr = (MultipartHttpServletRequest)request;
CommonsMultipartFile f = (CommonsMultipartFile) mpr.getFile("productPic");
def okcontents = ['image/png', 'image/jpeg', 'image/gif']
if (! okcontents.contains(f.getContentType())) {
message = "Avatar must be one of: ${okcontents}"
render(view:'uploadForm', model:[message: message])
return;
}
String type = f.getContentType().substring(6)
String baseImageName = java.util.UUID.randomUUID().toString();
baseImageName = "user${user.id}"
// Saving image in a folder assets/channelImage/, in the web-app, with the name: baseImageName
def downloadedFile = f //.getFile( "product.baseImage" )
String fileUploaded = fileUploadService.uploadFile( downloadedFile, "${baseImageName}.${type}", "assets/channelImage/" )
if( fileUploaded ){
user.avatarType = type
user.save()
message = "File Saved Successfully."
redirect(action: 'show', params: [userId: userId])
}
}
my service action where I am trying to delete before save >>>
def String uploadFile( MultipartFile file, String name, String destinationDirectory ) {
def serveletContext = ServletContextHolder.servletContext
def storagePath = serveletContext.getRealPath( destinationDirectory )
def storagePathDirectory = new File("${storagePath}/${name}").delete()
// Store file
if(!file.isEmpty()){
file.transferTo( new File("${storagePath}/${name}") )
println("Saved File: ${storagePath}/${name}")
return "${storagePath}/${name}"
}else{
println "File: ${file.inspect()} was empty"
return null
}
}
my show method in controller >>>
def show = {
Long uid = Long.parseLong(params.userId)
def avatarUser = User.get(uid)
String link = "user${avatarUser.id}.${avatarUser.avatarType}"
[link:link]
}
my view page >>>
<g:if test="${link}">
<img src="${resource(dir: 'assets/channelImage', file: "${link}")}" />
</g:if>