@Override
 public void insert(EventMember eventMember) {
   eventMember.setCreateTime(new Date());
   eventMember.setLastModifiedTime(eventMember.getCreateTime());
   String id = super.insert(eventMember);
   eventMember.set_id(id);
 }
 @Override
 public void update(EventMember eventMember) {
   eventMember.setLastModifiedTime(new Date());
   super.update(eventMember);
 }