Apache-POI sorting rows in excel

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

Poi has no built in sorting mechanism, though of course you are far from the first one with that need.

I think you are getting in trouble because you are moving rows that you are iterating over. I have run the code above and it seems what is happening is rows are disappearing from the sheet by the end of the code execution.

The question attempts to do an in-place modification of a read-in sheet. I believe that creating a second output sheet would be more appropriate.

So the basic approach would be read the sheet, sort in java just as you would treat any other sort problem, write to output sheet. If you did a map of the row number which is unique to the string value of the column you are interested in then you could sort the map by value. This sort of approach would work if you only foresaw the need to sort on a single column. In any event, it is not as simple as just choosing the sort menu option from within excel.

To sort rows you need to:

• copy all rows to temp
• sort rows in the temp
• remove all rows from sheet
• create new rows with values of sorted rows from temp

Code:

import org.apache.commons.compress.utils.Lists;
import org.apache.poi.hssf.usermodel.HSSFOptimiser;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.util.CellRangeAddress;

import java.util.List;

public static void sortSheet(Workbook workbook, Sheet sheet) {
        //copy all rows to temp
        List<Row> rows = Lists.newArrayList(sheet.rowIterator());
        //sort rows in the temp
        rows.sort(Comparator.comparing(cells -> cells.getCell(0).getStringCellValue()));
        //remove all rows from sheet
        removeAllRows(sheet);
        //create new rows with values of sorted rows from temp
        for (int i = 0; i < rows.size(); i++) {
            Row newRow = sheet.createRow(i);
            Row sourceRow = rows.get(i);
            // Loop through source columns to add to new row
            for (int j = 0; j < sourceRow.getLastCellNum(); j++) {
                // Grab a copy of the old/new cell
                Cell oldCell = sourceRow.getCell(j);
                Cell newCell = newRow.createCell(j);

                // If the old cell is null jump to next cell
                if (oldCell == null) {
                    newCell = null;
                    continue;
                }

                // Copy style from old cell and apply to new cell
                CellStyle newCellStyle = workbook.createCellStyle();
                newCellStyle.cloneStyleFrom(oldCell.getCellStyle());
                newCell.setCellStyle(newCellStyle);

                // If there is a cell comment, copy
                if (oldCell.getCellComment() != null) {
                    newCell.setCellComment(oldCell.getCellComment());
                }

                // If there is a cell hyperlink, copy
                if (oldCell.getHyperlink() != null) {
                    newCell.setHyperlink(oldCell.getHyperlink());
                }

                // Set the cell data type
                newCell.setCellType(oldCell.getCellType());

                // Set the cell data value
                switch (oldCell.getCellType()) {
                    case BLANK:
                        newCell.setCellValue(oldCell.getStringCellValue());
                        break;
                    case BOOLEAN:
                        newCell.setCellValue(oldCell.getBooleanCellValue());
                        break;
                    case ERROR:
                        newCell.setCellErrorValue(oldCell.getErrorCellValue());
                        break;
                    case FORMULA:
                        newCell.setCellFormula(oldCell.getCellFormula());
                        break;
                    case NUMERIC:
                        newCell.setCellValue(oldCell.getNumericCellValue());
                        break;
                    case STRING:
                        newCell.setCellValue(oldCell.getRichStringCellValue());
                        break;
                }
            }

            // If there are are any merged regions in the source row, copy to new row
            for (int j = 0; j < sheet.getNumMergedRegions(); j++) {
                CellRangeAddress cellRangeAddress = sheet.getMergedRegion(j);
                if (cellRangeAddress.getFirstRow() == sourceRow.getRowNum()) {
                    CellRangeAddress newCellRangeAddress = new CellRangeAddress(newRow.getRowNum(),
                            (newRow.getRowNum() +
                                    (cellRangeAddress.getLastRow() - cellRangeAddress.getFirstRow()
                                    )),
                            cellRangeAddress.getFirstColumn(),
                            cellRangeAddress.getLastColumn());
                    sheet.addMergedRegion(newCellRangeAddress);
                }
            }
        }

    }

    private static void removeAllRows(Sheet sheet) {
            for (int i = 0; i < sheet.getLastRowNum(); i++) {
                sheet.removeRow(sheet.getRow(i));
            }
        }