Add new util method.

DEVSIX-1668

Author: ars18wrw

io/src/main/java/com/itextpdf/io/util/UrlUtil.java

@@ -120,4 +120,14 @@ public static URL getFinalURL(URL initialUrl) throws IOException {
         }
         return finalUrl;
     }
+
+    /**
+     * This method gets uri string from a file.
+     * @param filename a given filename
+     * @return a uri string
+     */
+    public static String getFileUriString(String filename) throws MalformedURLException {
+        return new File(filename).toURI().toURL().toExternalForm();
+    }
+
 }