如何附加两个不同类型的列表？ [复制]

Question

List<ExpenseDetailsWrapper> expenseDataList = reimbursementLocalService
                        .getAllExpenseByReimbursementId(reimbursementId);

                long fileEntryId = 0;
                String previewURL = StringPool.BLANK;
                List<String> billUrlData = new ArrayList<String>();
                List<String> finalMerge = new ArrayList<String>();
                try { 
                    for (int i = 0; i < expenseDataList.size(); i++) {
                         fileEntryId = expenseDataList.get(i).getFileEntryId();
                         if (fileEntryId > 0) {
                            FileEntry fileEntry = DLAppLocalServiceUtil.getFileEntry(fileEntryId);
                            previewURL = DLUtil.getPreviewURL(fileEntry, fileEntry.getFileVersion(), themeDisplay, StringPool.BLANK);
                        }           
                         renderRequest.setAttribute("previewUrl", previewURL);
                         finalMerge.add(billUrlData);
                         finalMerge.add(expenseDataList);//**Error is here**The method addAll(Collection<? extends String>) in the type List<String> is not applicable for the arguments (List<ExpenseDetailsWrapper>)
                         LOG.info("File Entries"+fileEntryId);
                    }
                    LOG.info(billUrlData);
                    renderRequest.setAttribute("previewUrl", billUrlData);
                    renderRequest.setAttribute("expenseDataList", expenseDataList);
                } catch (Exception e) {
                    e.printStackTrace();
                }

我有一个带有 POJO 的列表和另一个带有 String 的列表。但是当我尝试将这两个列表添加到一个列表中时，它给了我错误 我可以附加两个不同类型的列表吗？？

Answer 1

是的，您可以使用 List<Object> expenseDataList，但在检索时您需要小心并投射它。

for(Object obj : expenseDataList)
{
  if(obj instanceof YourPOJO)
//take action
}