Question

I’d like to sort rows in a sheet by one of string column. I tried to achive that using Sheet.shiftRows method, but I cannot manage with that. It doesn’t switch positions of rows in my method. What’s wrong in my code? Or maybe there is better way to sort rows by any String column in excel?

/**
 * Sorts (A-Z) rows by String column
 * @param sheet - sheet to sort
 * @param column - String column to sort by
 * @param rowStart - sorting from this row down
 */
private void sortSheet(Sheet sheet, int column, int rowStart) {
    boolean sorting = true;
    int lastRow = sheet.getLastRowNum();
    while (sorting == true) {
        sorting = false;
        for (Row row : sheet) {
            // skip if this row is before first to sort
            if (row.getRowNum()<rowStart) continue;
            // end if this is last row
            if (lastRow==row.getRowNum()) break;
            Row row2 = sheet.getRow(row.getRowNum()+1);
            if (row2 == null) continue;
            String firstValue = (row.getCell(column) != null) ? row.getCell(column).getStringCellValue() : "";
            String secondValue = (row2.getCell(column) != null) ? row2.getCell(column).getStringCellValue() : "";
            //compare cell from current row and next row - and switch if secondValue should be before first
            if (secondValue.compareToIgnoreCase(firstValue)<0) {                    
                sheet.shiftRows(row2.getRowNum(), row2.getRowNum(), -1);
                sheet.shiftRows(row.getRowNum(), row.getRowNum(), 1);
                sorting = true;
            }
        }
    }
}

Any idea how to manage row sorting in a sheet?

UPDATE The method above works since Apache-POI 3.9 version.

EDIT: Added missing bracket -helvio

Answer 1

Now I now why it’s not working. There is a bug in shiftRows method. When third argument (number of rows to shift) is negative, it causes troubles.

This is described here: https://issues.apache.org/bugzilla/show_bug.cgi?id=53798

UPDATE
This bug has been fixed from version 3.9