Write data into Excel sheet java

Question

I have 3 lists namely list1, list2 and list3. And I want to display these lists in an excel sheet as 3 columns. For example the values in list 1 should be displayed in the first column of Excel sheet. I am adding all the 3 lists to a final list as below and able to display them as separate rows and no idea how can i display as columns. I am using apachepoi.

List<List> finalList = new ArrayList<List>();
     finalList .add(list1);
     finalList .add(list2);
 WritingToExcelFile(List<List> l1) throws Exception {  //passing finalList here
    try {
        for (int j = 0; j < l1.size(); j++) {
            Row row = firstSheet.createRow(rownum);
            List<String> l2 = l1.get(j);
            for (int k = 0; k < l2.size(); k++) {
                Cell cell = row.createCell(k);
                cell.setCellValue(l2.get(k));
            }
            rownum++;
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
    }
}

Answer 1

Assuming your lists are all the same size, why not something like:

Sheet s = wb.createSheet();
for (int i=0; i<firstList.size(); i++) {
   Row r = s.createRow(i);
   r.createCell(0).setCellValue( list1.get(i) );
   r.createCell(1).setCellValue( list2.get(i) );
   r.createCell(2).setCellValue( list3.get(i) );
}

Add extra error handling if your lists might not be the same length, and extra logic if you need to do formatting / dates / etc for the list contents