fix format of date no effect

@@ -2008,10 +2008,14 @@ public class DateUtil {
     }
 
     public static String formatDate(Integer time, String pattern) {
-        if (time == null || pattern == null) {
+        if (time == null ) {
             return null;
         }
-        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+        if( pattern == null){
+            pattern = yyyy_MM_dd_HH_mm_SS;
+        }
+
+        SimpleDateFormat dateFormat = new SimpleDateFormat(pattern);
         return dateFormat.format(new Date((long) time * 1000));
     }