为什么附件加不上

Question

 ==============附件========================
        Set<Upload> set = (HashSet) request.getSession().getAttribute("upload");
Set<Upload> oldset = modiTable1.getUploadset();
 Set<Upload> newset = new HashSet<Upload>();
if(set!=null){
for(Upload u:set){
u.setBiaoid(2);
u.setRecopyId(recopyId);
u.setDeleteNum(0);
newset.add(u);
}
}
if(oldset!=null){
for(Upload u:oldset){
   int dNum=u.getDeleteNum();
   if(dNum==0){
               u.setBiaoid(2);
               u.setRecopyId(recopyId);
newset.add(u);}
}
}
modiTable1.setUploadset(newset);
request.getSession().setAttribute("upload", null);

// =======================================
technologyStoreService.addOrUpdateModiTable(modiTable1);