Develop Reference

Delete multiple rows in Excel file using Apache POI

I have very little knowledge of Apache POI. Is there any optimized way to delete the Excel rows quickly using Apache POI and Java?
It is taking more than two hours to remove the 11000 rows and is it possible to delete multiple rows at a time?
I have used the following code:
for (int s = rowNum; s < 11000; s++) {
Row r = sheet.getRow(s);
if(r != null) {
sheet.removeRow(r);
}
}

Unfortunately, as of apache-poi-5.0.0 it cannot be done any faster.
The problem of removing a row from an XSSFSheet may look linear but is actually quadratic.
So when you try to remove mutliple XSSFRows from an XSSFSheet, you are also removing the XSSFCells associated with it. Thus, more the number of XSSFCells the slower it gets.
Code from XSSFSheet:
/**
* Remove a row from this sheet. All cells contained in the row are removed as well
*
* #param row the row to remove.
*/
#Override
public void removeRow(Row row) {
if (row.getSheet() != this) {
throw new IllegalArgumentException("Specified row does not belong to this sheet");
}
// collect cells into a temporary array to avoid ConcurrentModificationException
ArrayList<XSSFCell> cellsToDelete = new ArrayList<>();
for (Cell cell : row) {
cellsToDelete.add((XSSFCell)cell);
}
for (XSSFCell cell : cellsToDelete) {
row.removeCell(cell);
}
final int rowNum = row.getRowNum();
// Performance optimization: explicit boxing is slightly faster than auto-unboxing, though may use more memory
//noinspection UnnecessaryBoxing
final Integer rowNumI = Integer.valueOf(rowNum); // NOSONAR
// this is not the physical row number!
final int idx = _rows.headMap(rowNumI).size();
_rows.remove(rowNumI);
worksheet.getSheetData().removeRow(idx);
// also remove any comment located in that row
if(sheetComments != null) {
for (CellAddress ref : getCellComments().keySet()) {
if (ref.getRow() == rowNum) {
sheetComments.removeComment(ref);
}
}
}
}
My suggestion would be to copy the XSSFRows from the existing XSSFSheet to a new XSSFSheet and then remove the previous XSSFSheet. Use this iff, number of XSSFRows to be deleted is greater than the number of XSSFRows to be copied.
private void copyRowsAndDeleteSheet(XSSFWorkbook workbook) {
XSSFSheet srcSheet = workbook.createSheet();
// Inserting dummy data
for (int i = 0; i < 11000; i++) {
XSSFRow row = srcSheet.createRow(i);
row.createCell(0).setCellType(CellType.STRING);
row.getCell(0).setCellValue("Hello" + i);
}
// Sheet to be copied to
XSSFSheet destSheet = workbook.createSheet();
// Defines how the cell should be copied
CellCopyPolicy policy = new CellCopyPolicy().createBuilder().cellStyle(true).build();
for (int i = 0; i < 100; i++) {
// Row to be copied
XSSFRow srcRow = srcSheet.getRow(i);
// Inserting into a i+1 instead of i to avoid IllegalArgumentException throw by FormulaShifter
destSheet.createRow(i + 1).copyRowFrom(srcRow, policy);
}
// Shifting the rows up by 1 row to match source sheet
destSheet.shiftRows(1, 100, -1);
// removing the source sheet
workbook.removeSheetAt(workbook.getSheetIndex(srcSheet));
}
Note: copyRowFrom() is still beta so it would be wise to not use it in a production environment.

How to delete the reflected row of the second JTable if the user selects another row in the first JTable?

I am having trouble deleting the previous row of my second table of my Products Stock In GUI in Java.
The flow of the functionality of my GUI is this:
If the user will select a row in the first table of the GUI, the values of those rows will be reflected on the second rows
If the user will select another/different row in the first table, the previous reflected row which was selected in the first table must be deleted and is replaced by the current selected row.
To sum it up, I have to replace/delete the previous reflected rows if I will select a different row in the first table then replace that previous selected row into the current selected row.
Here's my source code:
private void firstTableMouseClicked(java.awt.event.MouseEvent evt) {
DefaultTableModel secondTblmodel = (DefaultTableModel) secondTable.getModel();
int selectPRoww = firstTable.getSelectedRow();
for (int x = 0; x < ProductAllData2[selectPRoww].length; x++) {
//ProductAllData2 is a 3D array
if (ProductAllData2[selectPRoww][x][0] != null) {
if (setRowCountID2 == 0)
secondTblmodel.setRowCount(0);
//Reflects and displays the values of the selected
// row from the first table to the second table
secondTblmodel.addRow(ProductAllData2[selectPRoww][x]);
// deletes previous row if index of selected row is
// greater than the previous selected row (doesn't work)
if (selectPRoww > selectPRoww) {
secondTblmodel.removeRow(selectPRoww - 1);
}
// deletes previous row if index of selected row is
// less than the previous selected row (doesn't work)
if (selectPRoww < selectPRoww) {
secondTblmodel.removeRow(selectPRoww + 1);
}
setRowCountID2++;
}
}
}
Am I missing something in my functionality or do I need to modify the for loops?

In my opinion, your logic should not be like this.
As the second table (View) depends on the selection of the first table, then the second table should always be cleared, then you do this logic.
//Reflects and displays the values of the selected
// row from the first table to the second table
secondTblmodel.addRow(data);
Important Point: Please use ListSelectionListener on table1, rather than depending on mouse clicks.
Example of usage:
table1.getSelectionModel().addListSelectionListener(new SharedListSelectionHandler());
class SharedListSelectionHandler implements ListSelectionListener {
public void valueChanged(ListSelectionEvent e) {
ListSelectionModel lsm = (ListSelectionModel) e.getSource();
int firstIndex = e.getFirstIndex();
int lastIndex = e.getLastIndex();
boolean isAdjusting = e.getValueIsAdjusting();
output.append("Event for indexes "
+ firstIndex + " - " + lastIndex
+ "; isAdjusting is " + isAdjusting
+ "; selected indexes:");
if (lsm.isSelectionEmpty()) {
output.append(" <none>");
} else {
// Find out which indexes are selected.
int minIndex = lsm.getMinSelectionIndex();
int maxIndex = lsm.getMaxSelectionIndex();
for (int i = minIndex; i <= maxIndex; i++) {
if (lsm.isSelectedIndex(i)) {
output.append(" " + i);
}
}
}
output.append(newline);
}
}
How to Write a List Selection Listener | The Java™ Tutorials
Similar StackOverflow: Deleting row from JTable after valueChanged event is triggered

Apache poi "pull down" formatting

I have a requirement for apache poi to act like "pulling down" formatting in excel. So taking a sample row, getting the "formatting" in each cell and applying it to all the cells below. Formatting according to the requirement includes number formats and the cells' background colors changing depending on the value. So I wrote a class that gets the CellStyle from the example row's cells and applies it according.
public class FormatScheme implements ObjIntConsumer<Sheet> {
private Map<Integer, CellStyle> cellFormats = new LinkedHashMap<>();
public static FormatScheme of(Row row, int xOffset){
FormatScheme scheme = new FormatScheme();
for (int i = xOffset; i < row.getLastCellNum(); i++) {
Cell cell = row.getCell(i);
if(cell==null) continue;
scheme.cellFormats.put(i, cell.getCellStyle());
}
return scheme;
}
#Override
public void accept(Sheet sheet, int rowIndex) {
Row row = sheet.getRow(rowIndex);
if(row==null) row=sheet.createRow(rowIndex);
Row finalRow = row;
cellFormats.entrySet().forEach(entry -> {
Cell cell = finalRow.getCell(entry.getKey());
if(cell==null) cell= finalRow.createCell(entry.getKey());
cell.setCellStyle(entry.getValue());
});
}
private FormatScheme(){}
}
This does seem to work for the number formats but doesn't grab the changing background colors. ~I guess, I'm missing something.~
With help from Alex Richter I understand that I need to use the sheet's SheetConditionalFormatting. How can I get the ConditionalFormatting that are currently applied to a cell and expand the range the affect downward?

Your question is not really clear. But I suspect you want copying formatting from one target row to multiple adjacent following rows. And you want expanding the ranges of conditional formatting rules too, so that the cells in the adjacent following rows also follow that rules. So the same what Excel's format painter does if you select one row, then click format painter and then select multiple adjacent following rows.
How to copy cell styles, you have got already. But why doing this that complicated? Copying cell styles form one cell to another is a one-liner: targetCell.setCellStyle(sourceCell.getCellStyle());.
Second we should copy possible row style too. The following example has a method void copyRowStyle(Row sourceRow, Row targetRow) for this.
To expand the ranges for the conditional formatting rules we need getting the rules which are applied to the cell. The rules are stored on sheet level. So we need traversing the SheetConditionalFormatting to get the rules where the cell is in range. The following example has a method List<ConditionalFormatting> getConditionalFormattingsForCell(Cell cell) for this.
Having this we can expand the ranges of the conditional formatting rules. The following example has a method void expandConditionalFormatting(Cell sourceCell, Cell targetCell) for this. It expands the ranges of the conditional formatting rules from sourceCell to targetCell.
Complete example which shows the principle:
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.usermodel.ConditionalFormatting;
import org.apache.poi.ss.util.*;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.List;
import java.util.ArrayList;
class ExcelCopyFormatting {
static List<ConditionalFormatting> getConditionalFormattingsForCell(Cell cell) {
List<ConditionalFormatting> conditionalFormattingList = new ArrayList<ConditionalFormatting>();
Sheet sheet = cell.getRow().getSheet();
SheetConditionalFormatting sheetConditionalFormatting = sheet.getSheetConditionalFormatting();
for (int i = 0; i < sheetConditionalFormatting.getNumConditionalFormattings(); i++) {
ConditionalFormatting conditionalFormatting = sheetConditionalFormatting.getConditionalFormattingAt(i);
CellRangeAddress[] cellRangeAddressArray = conditionalFormatting.getFormattingRanges();
for (CellRangeAddress cellRangeAddress : cellRangeAddressArray) {
if (cellRangeAddress.isInRange(cell)) {
conditionalFormattingList.add(conditionalFormatting);
}
}
}
return conditionalFormattingList;
}
static void expandConditionalFormatting(Cell sourceCell, Cell targetCell) {
List<ConditionalFormatting> conditionalFormattingList = getConditionalFormattingsForCell(sourceCell);
for (ConditionalFormatting conditionalFormatting : conditionalFormattingList) {
CellRangeAddress[] cellRangeAddressArray = conditionalFormatting.getFormattingRanges();
for (int i = 0; i < cellRangeAddressArray.length; i++) {
CellRangeAddress cellRangeAddress = cellRangeAddressArray[i];
if (cellRangeAddress.isInRange(sourceCell)) {
if (cellRangeAddress.getFirstRow() > targetCell.getRowIndex()) {
cellRangeAddress.setFirstRow(targetCell.getRowIndex());
}
if (cellRangeAddress.getFirstColumn() > targetCell.getColumnIndex()) {
cellRangeAddress.setFirstColumn(targetCell.getColumnIndex());
}
if (cellRangeAddress.getLastRow() < targetCell.getRowIndex()) {
cellRangeAddress.setLastRow(targetCell.getRowIndex());
}
if (cellRangeAddress.getLastColumn() < targetCell.getColumnIndex()) {
cellRangeAddress.setLastColumn(targetCell.getColumnIndex());
}
cellRangeAddressArray[i] = cellRangeAddress;
}
}
conditionalFormatting.setFormattingRanges(cellRangeAddressArray);
}
}
static void copyRowStyle(Row sourceRow, Row targetRow) {
if (sourceRow.isFormatted()) {
targetRow.setRowStyle(sourceRow.getRowStyle());
}
}
static void copyCellStyle(Cell sourceCell, Cell targetCell) {
targetCell.setCellStyle(sourceCell.getCellStyle());
}
static void copyFormatting(Sheet sheet, int fromRow, int upToRow) {
Row sourceRow = sheet.getRow(fromRow);
for (int r = fromRow + 1; r <= upToRow; r++) {
Row targetRow = sheet.getRow(r);
if (targetRow == null) targetRow = sheet.createRow(r);
copyRowStyle(sourceRow, targetRow);
for (Cell sourceCell : sourceRow) {
Cell targetCell = targetRow.getCell(sourceCell.getColumnIndex());
if (targetCell == null) targetCell = targetRow.createCell(sourceCell.getColumnIndex());
copyCellStyle(sourceCell, targetCell);
if (r == upToRow) {
if (getConditionalFormattingsForCell(sourceCell).size() > 0) {
expandConditionalFormatting(sourceCell, targetCell);
}
}
}
}
}
public static void main(String[] args) throws Exception {
//Workbook workbook = WorkbookFactory.create(new FileInputStream("./Workbook.xls")); String filePath = "./WorkbookNew.xls";
Workbook workbook = WorkbookFactory.create(new FileInputStream("./Workbook.xlsx")); String filePath = "./WorkbookNew.xlsx";
Sheet sheet = workbook.getSheetAt(0);
copyFormatting(sheet, 1, 9); // copy formatting from row 2 up to row 10
FileOutputStream out = new FileOutputStream(filePath);
workbook.write(out);
out.close();
workbook.close();
}
}

How to calculate average values with integer and decimal?

Here I want average of row5, row6, row7, then I want to check with another table whether calculation is right or wrong. How to achieve this?
for(WebElement rowElement:TotalRowCount)
{
List<WebElement> TotalColumnCount=rowElement.findElements(By.xpath("td/span"));
int ColumnIndex=1;
for(WebElement colElement:TotalColumnCount)
{
String s=colElement.getText().replace("%", "").replace(",","");
if(!s.isEmpty()&&!s.equals("NA"))
{
if(s.contains(".")||s.contains("-"))
{
double d=Double.parseDouble(s);
System.out.println("Row "+RowIndex+"Double value is"+d);
}
else
{
int x1=Integer.parseInt(s);
System.out.println("Row "+RowIndex+"Integer value"+x1);
}
ColumnIndex=ColumnIndex+1;
}
else{/*do nothing*/}
}
RowIndex=RowIndex+1;
}
Output:
Row 5Integer value140
Row 6Integer value51
Row 6Integer value52
Row 6Integer value51
Row 6Integer value36
Row 7Double value is30.0
Row 7Double value is30.65
Row 7Double value is29.38

How to collect references from Excel in an arraylist

I am using arraylist to collect reference IDs of the product from Excel sheet. I am using POI. The issue is that I don't want to include blank cells in my arraylist. Here is my code:
public static ArrayList<String> extractExcelContentByColumnIndex()
{
ArrayList<String> columnData=null;
try
{
FileInputStream fis=new FileInputStream(excel_path);
Workbook wb=WorkbookFactory.create(fis);
Sheet sh=wb.getSheet(sheetname);
Iterator<Row> rowIterator=sh.iterator();
columnData=new ArrayList<>();
while(rowIterator.hasNext())
{
Row row=rowIterator.next();
Iterator<Cell> cellIterator=row.cellIterator();
while(cellIterator.hasNext())
{
Cell cell=cellIterator.next();
if((row.getRowNum()>=3) && (row.getRowNum()<=sh.getPhysicalNumberOfRows()))
{
if(cell.getColumnIndex()==3)// column under watch
{
columnData.add(cell.getStringCellValue());
Collections.sort(columnData);
}
}
}
}
fis.close();
}
catch(Exception e)
{
e.printStackTrace();
}
System.err.println("DL BoM = "+columnData);
return columnData;
}
And output is :
DL BoM = [, , , , , , 03141, 03803, 08002, 08012, 08817, 13124, A9C22712, A9N21024, A9N21027, A9N21480]

The POI documentation provides some useful information to that specific topic.
Iterate over cells, with control of missing / blank cells
In some cases, when iterating, you need full control over how missing
or blank rows and cells are treated, and you need to ensure you visit
every cell and not just those defined in the file. (The CellIterator
will only return the cells defined in the file, which is largely those
with values or stylings, but it depends on Excel).
In cases such as these, you should fetch the first and last column
information for a row, then call getCell(int, MissingCellPolicy) to
fetch the cell. Use a MissingCellPolicy to control how blank or null
cells are handled.
// 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);
if (r == null) {
// This whole row is empty
// Handle it as needed
continue;
}
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
}
}
}
Source: http://poi.apache.org/spreadsheet/quick-guide.html#Iterator

Before getting the cell value.. check if it's not empty
if(cell.getColumnIndex()==3)// column under watch
{
if(cell.getStringCellValue().Trim() != "")
{
columnData.add(cell.getStringCellValue());
}
Collections.sort(columnData);
}