public String getUrl() {
   try {
     return Base64.decode(getEvaKey());
   } catch (Exception e) {
     return "";
   }
 }
 public void setUrl(String url) {
   try {
     setEvaKey(Base64.encode(url));
   } catch (Exception e) {
     setEvaKey("");
   }
 }
 public static String getUrlFormKey(String key) {
   try {
     return Base64.decode(key);
   } catch (Exception e) {
     return "";
   }
 }