Clojure Download a file

core.clj

(defn download-file [url dir]
  (let [my-file (last (.split url "/"))]
    (if-not (.exists  (io/as-file (str dir my-file)))
      (try
        (with-open [ in (io/input-stream url)
                    out (io/output-stream (str dir my-file))]
          (io/copy in out)
          (println  my-file " has been downloaded.")
          )
        (catch Exception e (str "caught exception:" (.getMessage e))))
      (print my-file "is already there"))))