How to read empty, but formated, Excel cells with Apache POI?

Question

I have a method for reading Excel cells using Apache POI , and it works fine. Well... almost fine.

public static ArrayList readXLsXFile() throws FileNotFoundException, IOException {

        ArrayList outListaExcel = new ArrayList();

        FileInputStream fis;
        ptxf= new FileInputStream(pathToExcelFile);
        XSSFWorkbook workbook = new XSSFWorkbook(ptxf);
        XSSFSheet sheetAr = workbook.getSheetAt(0);
        Iterator rowsAr = sheetAr.rowIterator();
        while (rowsAr.hasNext()) {
            XSSFRow row1 = (XSSFRow) rowsAr.next();
            Iterator cellsAr = row1.cellIterator();
            ArrayList<String> arr;
            arr = new ArrayList();
            while (cellsAr.hasNext()) {
                XSSFCell cell1 = (XSSFCell) cellsAr.next();
                arr.add(String.valueOf(cell1));
            }
            outListaExcel.add(arr);
        }
        return outListaExcel;
    }

If cells are formatted, for example if whole A column have borders, then it will keep reading empty cells giving me empty strings. How to ignore those empty(formated) cells?

So readXLsXFile will give me an ArryList with

[0] -> [1][2]
[1] -> [3][4] 

But it will also give ten more nodes with empty strings,because coloumn A is formated with borders.

edit after Gagravarr answer.

I can avoid checking wether subList is empty and then do not add it to mainList . But in the case of some very large .xls files and if there is many of them it will take too long, and generaly I think it is not a good practice.

My question was if there is something for rows , like it is for cells that I have overlooked.

 ArrayList<ArrayList<String>>mainLista = new ArrayList<ArrayList<String>>();
for (int rowNum = rowStart; rowNum < rowEnd; rowNum++) {
        Row r = sheet.getRow(rowNum);
        int lastColumn = r.getLastCellNum();
        ArrayList<String> subList = new ArrayList<String>();
        for (int cn = 0; cn < lastColumn; cn++) {
            Cell c = r.getCell(cn, Row.RETURN_BLANK_AS_NULL);

            if (c != null) {
                subList.add(c.getStringCellValue());
            } else {
            }
        }
        if (!subList.isEmpty() ){  // I think it is not good way
        mainLista.add(subList);}   // to do this, because it still reads 
    }                              // an empty rows  

Answer 1

As explained in the Apache POI Documentation on Iterate over rows and cells , the iterators only give you the rows and cells which are defined and have/had content.

If you want to fetch cells with full control over blank or empty cells, you need to instead use something like:

// Decide which rows to process
int rowStart = Math.min(15, sheet.getFirstRowNum());
int rowEnd = Math.max(1400, sheet.getLastRowNum());

for (int rowNum = rowStart; rowNum < rowEnd; rowNum++) {
   Row r = sheet.getRow(rowNum);

   int lastColumn = Math.max(r.getLastCellNum(), MY_MINIMUM_COLUMN_COUNT);

   for (int cn = 0; cn < lastColumn; cn++) {
      Cell c = r.getCell(cn, Row.RETURN_BLANK_AS_NULL);
      if (c == null) {
         // The spreadsheet is empty in this cell
      } else {
         // Do something useful with the cell's contents
      }
   }
}

If you want to fetch blank cells (typically those with styling but no values), play with the other Missing Cell Policies, eg RETURN_NULL_AND_BLANK

Answer 2

设置B列的边框，在我的例子中它帮助了我