def unzipFile(File file) {
    cleanupFolder()
    def zipFile = new ZipFile(file)
    zipFile.entries().each { it ->
        def path = Paths.get('c:\\folder\\' + it.name)
        if(it.directory){
            Files.createDirectories(path)
        }
        else {
            def parentDir = path.getParent()
            if (!Files.exists(parentDir)) {
                Files.createDirectories(parentDir)
            }
            Files.copy(zipFile.getInputStream(it), path)
        }
    }
}

private cleanupFolder() {
    FileUtils.deleteDirectory(new File('c:\\folder\\'))
}