We Keep Coding

Using Java to read and clean Excel file

I'm trying to create a Java application that can read and clean an Excel file in .xlsx format (by comparing it to a master list, also in Excel format) before writing it to a new Excel file. I also need to be able to post the cleaned file to a web app, but that's for later.
I'm using Apache POI, and have been able to successfully read the Excel file (in the output section in Eclipse it doesn't start from the first row though).
Here's where I'm stuck. I've been able to read the rows using an iterator, but how do I extract all these values to variables? Can I create a data table?
public class ReadAndCleanExcel {
public void readExcel(String filePath) {
Object[][] data = null;
final DataFormatter df = new DataFormatter();
try {
FileInputStream file = new FileInputStream(new File(filePath));
//Create Workbook instance holding reference to .xlsx file
XSSFWorkbook workbook = new XSSFWorkbook(file);
//Get first/desired sheet from the workbook
XSSFSheet sheet = workbook.getSheetAt(0);
//Iterate through each rows one by one
Iterator<Row> rowIterator = sheet.iterator();
int rownum = 0;
int colnum = 0;
Row r=rowIterator.next();
int rowcount=sheet.getLastRowNum();
int colcount=r.getPhysicalNumberOfCells();
data = new Object[rowcount][colcount];
while (rowIterator.hasNext()) {
Row row = rowIterator.next();
//For each row, iterate through all the columns
Iterator<Cell> cellIterator = row.cellIterator();
colnum = 0;
while (cellIterator.hasNext()) {
Cell cell = cellIterator.next();
//Check the cell type and format accordingly
data[rownum][colnum] = df.formatCellValue(cell);
System.out.print(df.formatCellValue(cell).toUpperCase() + " ");
colnum++;
}
rownum++;
System.out.println();
}
file.close();
workbook.close();
} catch (Exception e) {
e.printStackTrace();
}
}

File Path not changing in code

So I have created a class that searches an excel file and prints all the rows and columns of the file. Now I have an exception file not found error. In order to fix this error I have changed the file path in the code but for some reason I get the same error and the error message in the console shows the previous file path I was using that gave me error.
I know the new file path is correct but Eclipse doesn't seem to recognize that the code has been updated. Here is the code from the class:
public class ExcelReader {
public static final String SAMPLE_XLSX_FILE_PATH = "K:\\Documents\\Project\\Netword_GUI\\Netword_GUI\\src\\libs\\cc2017.xlsx";
public static void main(String[] args) throws IOException, InvalidFormatException {
// Creating a Workbook from an Excel file (.xls or .xlsx)
Workbook workbook = WorkbookFactory.create(new File(SAMPLE_XLSX_FILE_PATH));
// Retrieving the number of sheets in the Workbook
System.out.println("Workbook has " + workbook.getNumberOfSheets() + " Sheets : ");
/*
=============================================================
Iterating over all the sheets in the workbook (Multiple ways)
=============================================================
*/
// You can obtain a sheetIterator and iterate over it
Iterator<Sheet> sheetIterator = workbook.sheetIterator();
System.out.println("Retrieving Sheets using Iterator");
while (sheetIterator.hasNext()) {
Sheet sheet = sheetIterator.next();
//System.out.println(sheet.getRow(0));
System.out.println("=> " + sheet.getSheetName());
}
// Getting the Sheet at index zero
Sheet sheet = workbook.getSheetAt(0);
// Create a DataFormatter to format and get each cell's value as String
DataFormatter dataFormatter = new DataFormatter();
// You can obtain a rowIterator and columnIterator and iterate over them
System.out.println("\n\nIterating over Rows and Columns using Iterator\n");
Iterator<Row> rowIterator = sheet.rowIterator();
while (rowIterator.hasNext()) {
Row row = rowIterator.next();
// Now let's iterate over the columns of the current row
Iterator<Cell> cellIterator = row.cellIterator();
while (cellIterator.hasNext()) {
Cell cell = cellIterator.next();
String cellValue = dataFormatter.formatCellValue(cell);
System.out.print(cellValue + "\t");
}
System.out.println();
}
if (sheet.getActiveCell() == null) {
// Closing the workbook
workbook.close();
}
}
}
Now here is the error message displayed in the console:
Exception in thread "main" java.io.FileNotFoundException:
C:\Users\User\Dropbox\Placement\Private_Backup\Netword_GUI\Netword_GUI\src\cc2017.xlsx
at
org.apache.poi.ss.usermodel.WorkbookFactory.create(WorkbookFactory.java:250)
at
org.apache.poi.ss.usermodel.WorkbookFactory.create(WorkbookFactory.java:226)
at
org.apache.poi.ss.usermodel.WorkbookFactory.create(WorkbookFactory.java:205)
at ExcelReader.main(ExcelReader.java:13)
Notice: The file path in the console is different to the file path in the code. Previously the file path in the error message was in the code this is because I have the same class on another computer so the file path was changed as the location is different on the computer I am currently working on.

Sometimes the build in Eclipse is not up to date.
In that case you should clean and re-build your project (from the "Project" menu)

could you please add your code to make every one get the big picture of your code to give you a correct answer
try this one
File f=new File(fixed_file_path);
Workbook workbook = WorkbookFactory.create(f);

Sort excel by a column using shiftRows- Apache POI - XmlValueDisconnectedException

I have an XSSFWorkbook with n number of columns. And my requirement is to sort the entire sheet by the first column.
I referred to this link but did not get any information about sorting.
I have also tried the code from here but it gives exception at
sheet.shiftRows(row2.getRowNum(), row2.getRowNum(), -1);
I am using Apache POI 3.17.
Anyone has any suggestion or solution?

There seem to be a bug in POI when shifting columns, they say it was fixed in 3.9 but I used 3.17 and still have it:
Exception in thread "main" org.apache.xmlbeans.impl.values.XmlValueDisconnectedException
at org.apache.xmlbeans.impl.values.XmlObjectBase.check_orphaned(XmlObjectBase.java:1258)
at org.openxmlformats.schemas.spreadsheetml.x2006.main.impl.CTRowImpl.getR(Unknown Source)
at org.apache.poi.xssf.usermodel.XSSFRow.getRowNum(XSSFRow.java:394)
...
I assume it is the same you have. So I worked out an other way:
Sort your rows, then create a new workbook and copy rows in the correct order.
Then write this sorted workbook to the original file.
For simplicity, I assume all cell values are Strings. (if not, then modify accordingly)
private static final String FILE_NAME = "/home/userName/Workspace/fileToSort.xlsx";
public static void main(String[] args) {
Workbook originalWorkbook;
//create a workbook from your file
try(FileInputStream excelFile = new FileInputStream(new File(FILE_NAME))) {
originalWorkbook = new XSSFWorkbook(excelFile);
} catch (IOException e) {
throw new RuntimeException("Couldn't open file: " + FILE_NAME);
}
Sheet originalSheet = originalWorkbook.getSheetAt(0);
// Create a SortedMap<String, Row> where the key is the value of the first column
// This will automatically sort the rows
Map<String, Row> sortedRowsMap = new TreeMap<>();
// save headerRow
Row headerRow = originalSheet.getRow(0);
Iterator<Row> rowIterator = originalSheet.rowIterator();
// skip header row as we saved it already
rowIterator.next();
// sort the remaining rows
while(rowIterator.hasNext()) {
Row row = rowIterator.next();
sortedRowsMap.put(row.getCell(0).getStringCellValue(), row);
}
// Create a new workbook
try(Workbook sortedWorkbook = new XSSFWorkbook();
FileOutputStream out = new FileOutputStream(FILE_NAME)) {
Sheet sortedSheet = sortedWorkbook.createSheet(originalSheet.getSheetName());
// Copy all the sorted rows to the new workbook
// - header first
Row newRow = sortedSheet.createRow(0);
copyRowToRow(headerRow, newRow);
// then other rows, from row 1 up (not row 0)
int rowIndex = 1;
for(Row row : sortedRowsMap.values()) {
newRow = sortedSheet.createRow(rowIndex);
copyRowToRow(row, newRow);
rowIndex++;
}
// Write your new workbook to your file
sortedWorkbook.write(out);
} catch (Exception e) {
e.printStackTrace();
}
}
// Utility method to copy rows
private static void copyRowToRow(Row row, Row newRow) {
Iterator<Cell> cellIterator = row.cellIterator();
int cellIndex = 0;
while(cellIterator.hasNext()) {
Cell cell = cellIterator.next();
Cell newCell = newRow.createCell(cellIndex);
newCell.setCellValue(cell.getStringCellValue());
cellIndex++;
}
}
I tried it out on the following file
A B
---------------
Header1 Header2
a one
c three
d four
b two
and it sorts it this way:
A B
---------------
Header1 Header2
a one
b two
c three
d four

Is there any way to move horizontal scroll bar the sheet one column to the left using POI?

I have written a program that reads Excel template sheet. In which the first column was hidden. Now, I have a code that un-hide the excel column programmatically (so Column start from A1).
I'm using Apache POI 3.16 version.
When I open a file, it should show me a column from A1 instead it shows me from B1 column.
When I write below code for XLS, It working properly but didn't work for an XLSX format.
sheet.showInPane(0, 0);
I need to manually move the horizontal scroll bar to view my first column. How should I achieve this programmatically to auto-scroll to the first column for XLSX format?
Here is my full code.
public Workbook readWorkBookAndWriteErrors(String bufId,String inputFile, String ext) throws Exception {
Workbook workBook =null;
Sheet sheet = null;
if(GlobalVariables.EXCEL_FORMAT_XLS.equalsIgnoreCase(ext)){
// Get the workbook instance for XLS file
workBook = new HSSFWorkbook(new FileInputStream(inputFile));
}else{
// Get the workbook instance for XLSX file
workBook = new XSSFWorkbook(new FileInputStream(inputFile));
}
sheet = workBook.getSheetAt(0);
Row row = null;
if(sheet.isColumnHidden(0)){
sheet.setColumnHidden(0, false);
sheet.setActiveCell(new CellAddress("A1"));
sheet.showInPane(0, 0);
sheet.createFreezePane(0, 1);
Iterator<Row> rowIterator = sheet.iterator();
int rowIndex = 1;
while (rowIterator.hasNext()) {
row = rowIterator.next();
if(rowIndex == 1){
rowIndex++;
continue;
}
Cell cell = row.createCell(0);
cell.setCellValue("error message");
rowIndex++;
}
}
return workBook;
}

Here is the answer to my question. Please refer this Source
public Workbook readWorkBookAndWriteErrors(String bufId,String inputFile, String ext) throws Exception {
Workbook workBook =null;
Sheet sheet = null;
if(GlobalVariables.EXCEL_FORMAT_XLS.equalsIgnoreCase(ext)){
// Get the workbook instance for XLS file
workBook = new HSSFWorkbook(new FileInputStream(inputFile));
}else{
// Get the workbook instance for XLSX file
workBook = new XSSFWorkbook(new FileInputStream(inputFile));
}
sheet = workBook.getSheetAt(0);
Row row = null;
if(sheet.isColumnHidden(0)){
sheet.setColumnHidden(0, false);
if(sheet instanceof XSSFSheet){
CTWorksheet ctWorksheet = null;
CTSheetViews ctSheetViews = null;
CTSheetView ctSheetView = null;
XSSFSheet tempSheet = (XSSFSheet) sheet;
// First step is to get at the CTWorksheet bean underlying the worksheet.
ctWorksheet = tempSheet.getCTWorksheet();
// From the CTWorksheet, get at the sheet views.
ctSheetViews = ctWorksheet.getSheetViews();
// Grab a single sheet view from that array
ctSheetView = ctSheetViews.getSheetViewArray(ctSheetViews.sizeOfSheetViewArray() - 1);
// Se the address of the top left hand cell.
ctSheetView.setTopLeftCell("A1");
}else{
sheet.setActiveCell(new CellAddress("A1"));
sheet.showInPane(0, 0);
}
Iterator<Row> rowIterator = sheet.iterator();
int rowIndex = 1;
while (rowIterator.hasNext()) {
row = rowIterator.next();
if(rowIndex == 1){
rowIndex++;
continue;
}
Cell cell = row.createCell(0);
cell.setCellValue("error message");
rowIndex++;
}
}
return workBook;
}

If you are using latest C# NPOI, I made this utility function:
/// <summary>Set view position at given coordinates.</summary>
/// <param name="sheet">A reference to the Excel sheet.</param>
/// <param name="topLeftCell">The coordinates of the cell that will show in top left corner when you open the Excel sheet (example: "A1").</param>
/// <param name="onlyFirstView">If true, only first sheet view will have position adjusted. If false, every views from the sheet will have have position adjusted.</param>
public static void SetViewPosition(ref NPOI.SS.UserModel.ISheet sheet, string topLeftCell = "A1", bool onlyFirstView = true)
{
NPOI.OpenXmlFormats.Spreadsheet.CT_Worksheet worksheet = (NPOI.OpenXmlFormats.Spreadsheet.CT_Worksheet)(typeof(NPOI.XSSF.UserModel.XSSFSheet).GetField("worksheet", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance)?.GetValue((NPOI.XSSF.UserModel.XSSFSheet)sheet));
if (worksheet?.sheetViews?.sheetView != null && worksheet.sheetViews.sheetView.Count > 0)
{
if (onlyFirstView)
worksheet.sheetViews.sheetView[0].topLeftCell = topLeftCell;
else
foreach (NPOI.OpenXmlFormats.Spreadsheet.CT_SheetView view in worksheet.sheetViews.sheetView)
view.topLeftCell = topLeftCell;
}
}
Usage example:
NPOI.SS.UserModel.ISheet mySheet = myWorkbook.GetSheetAt(0);
// First sheet from our workbook opens with view set to top left corner (cell A1 visible in top left corner).
SetViewPosition(ref mySheet, "A1");

Below code worked for me to move horizontal scrollbar to required position.
Used apache poi libraries(poi, poi-ooxml).
((XSSFSheet)sheet).getCTWorksheet().getSheetViews().getSheetViewArray(0).setTopLeftCell("AE11");

how to get lastRowNum() from a specific file from a list of file in java

I am unable to get the lastRowNum() for a specific file while reading it from a folder.
The lastRowNum() method returns, last row after consolidating all the files in folder. I need a specific file .
Below is the code used
File[] listOfFiles = folder.listFiles();
for (File file : listOfFiles)
{
if (file.isFile()&&(file.getName().substring(file.getName().lastIndexOf('.')+1).equals("xlsx")))
{
Workbook workbook =WorkbookFactory.create(file.getAbsoluteFile());
Sheet sheet = workbook.getSheetAt(0);
int j = sheet.getLastRowNum();
System.out.println(j);
}
}
I am getting output as 340 which is the sum of all values in all files in the folder.
But for 1st sheet it should be 40. As in 1st sheet it contains 40 rows only

I used a break statement, in the loop, when the rowIterator.next() method returns null.This way one sheet is over and I again start over other sheet.
I am not calculating the lastRowNum() value to iterate through the rows.
This somehow, allowed me to read all the files.
Workbook workbook =WorkbookFactory.create(file.getAbsoluteFile());
Sheet sheet = workbook.getSheet("XYZ");
Iterator<Row> rowIterator = sheet.iterator();
rowIterator.next(); //Skipping headings
while (rowIterator.hasNext())
{
Row row = rowIterator.next();
Iterator<Cell> cellIterator = row.cellIterator();
SheetObject obj1= new SheetObject();
Cell cell = cellIterator.next();
if(cell.getCellType() == Cell.CELL_TYPE_BLANK) {
break;
}
obj1.setValue1(val);
String temp = cell.getStringCellValue();
obj1.setModule(temp); }
But still , the solution of the question is pending.