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Workbook takes long time to generate excel file

I'm trying to generate excel file with 200k records. But it is taking almost 2 hours to generate the file.
Here is my code of generating excel file.
Workbook workbook=null;
csvFileName = userId+"_Records_"+new SimpleDateFormat("yyyyMMddHHmmss")
.format(new Date())+".xls";
path = ReadPropertyFile.getProperties("download.reports.path");
misService.insertXLSRecord(ackNo,"-",null, VspCommonConstants.getIpFromRequest(request),
new Date(), userId,"N",userReportRoleId);
workbook = getWorkbook(path+csvFileName);
Sheet sheet = workbook.createSheet(WorkbookUtil.createSafeSheetName(studAppForm.get(0)
.getScheme_Id()+"_"+studAppForm.get(0).getEFP_Scholarship_Name(),'_'));
if(schemeQuestionData.containsKey(currSheetSchemeId))
createXLSHeaders(sheet,schemeQuestionData.get(currSheetSchemeId));
Row row = sheet.createRow(++rowCount);
currAppId=studAppForm.get(j).getApp_Id().toString();
jspTableAppIds.remove(jspTableAppIds.indexOf(new BigInteger(currAppId)));
writeBook(studAppForm.get(j), row);
Here is my createXLSHeaders method to create header
void createXLSHeaders( Sheet sheet, List<SchemeMasterBean> schemeMasterBeanList){
LOGGER.info("Creating XLS SheetHeaders for sheet "+sheet.getSheetName());
// Sheet sheet = workbook.createSheet();
Row header = sheet.createRow(0);
header.createCell(0).setCellValue("APPLICATION ID");
header.createCell(1).setCellValue("APPLICATION STATUS");
header.createCell(2).setCellValue("APPLICATION DATE");
header.createCell(3).setCellValue("SCHEME/SCHOLARSHIP APPLIED");
header.createCell(4).setCellValue("SCHEME ID");
header.createCell(5).setCellValue("STUDENT ID");
header.createCell(6).setCellValue("STUDENT FULL NAME");
.
.
.
62 heading...
int i=73;
if(schemeMasterBeanList!=null)
for(SchemeMasterBean schemeMasterBean :schemeMasterBeanList){
if(!schemeMasterBean.getSmSchemeType().equals("5") &&
!schemeMasterBean.getSmSchemeType().equals("6")){
header.createCell(i).setCellValue(schemeMasterBean.getSmScholarshipName());
i++;
}
}
}
and finally writebook method
private void writeBook(StudentAppFormVsp saf, Row row) throws JSONException {
Cell cell = row.createCell(0);
cell.setCellValue(saf.getApp_Id()!=null?saf.getApp_Id().toString():"");
cell = row.createCell(1);
cell.setCellValue(saf.getApp_Status()!=null?getApplicationStatusMap().get(saf.getApp_Status()):"");
cell = row.createCell(2);
cell.setCellValue(saf.getCrtn_time()!=null?saf.getCrtn_time().toString():"");
cell = row.createCell(3);
cell.setCellValue(saf.getEFP_Scholarship_Name()!=null?saf.getEFP_Scholarship_Name().toString():"");
cell = row.createCell(4);
cell.setCellValue(saf.getScheme_Id()!=null?saf.getScheme_Id().toString():"");
cell = row.createCell(5);
cell.setCellValue(saf.getStud_Id()!=null?saf.getStud_Id().toString():"");
.
.
62 rows
}
How to reduce the excel sheet generation time?

First: play around with memory for the application if possible.
Then: the tip on using a profiler is really worth the effort.
Any DOM, XML, Excel or otherwise often suffer from location references searching from top to the actual position.
Creating a DOM instead of writing sequentially is costly with respect to memory, and can slow things down. Maybe consider this.
You could make two loop: writing to a CSV file, and then creating an XLS(X).
Then you know where the complexity resides.
The following (I rewrote a bit) is slightly suspect: toString + new BigInteger points to a conversion; I hope not from BigInteger to String to BigInteger.
StudentAppFormVsp saf = studAppForm.get(j);
currAppId = saf.getApp_Id().toString();
jspTableAppIds.remove(jspTableAppIds.indexOf(BigInteger.valueOf(currAppId)));
writeBook(saf, row);

How to handle an empty numeric cell in POI

Is there any particular reason POI creates a numeric cell when in fact, it's actually empty? What happens is that by the time I get to that cell I obviously get an runtime error as I can't get the string value (it's a numeric cell, after all) and I can't get the numeric value either (can't get a number from an empty string) so my 2 questions would be:
How does POI got there?
Is there any way I can handle this scenario without having to explicitly go to my excel file?
UPDATE I:
After reading / parsing my excel file, POI generates the following XML for this particular cell:
<x:c r="AA2" t="n">
<x:v/>
</x:c>
My method is something like this:
final FileInputStream inputStream = new FileInputStream(new File("PATH/TO/FILE.xml"));
final XSSFWorkbook workbook = new XSSFWorkbook(inputStream);
final XSSFSheet sheet = workbook.getSheet("SHEET_NAME");
final int columnCount = sheet.getRow(0).getLastCellNum();
for (int rowNumber = 0; rowNumber <= sheet.getLastRowNum(); rowNumber++)
{
final XSSFRow row = sheet.getRow(rowNumber);
for (int column = 0; column < columnCount; column++)
{
// By now my cell would throw an exception if I attempt cell.getStringCellValue() or cell.getNumericCellValue() as cell.getCellType() returns "0" / NUMERIC
final XSSFCell cell = row.getCell(column);
...
}
}
I was thinking about adding an additional validation to determine whether the cell is empty by using the getRawValue() method, but not sure if there's a better way to handle this as it was obviously wrongly parsed.
UPDATE II
I've been able to reproduce this scenario by doing adding this as part of a unit test (I still don't understand why POI would fall into this scenario though):
final XLSXSheetConverterImpl xlsxSheetConverter = new XLSXSheetConverterImpl();
xlsxSheetConverter.setSheetName(SHEET_NAME);
xlsxSheetConverter.setFilePrefix(FILE_PREFIX);
XSSFWorkbook workbook = new XSSFWorkbook();
final XSSFSheet sheet = workbook.createSheet(SHEET_NAME);
final XSSFRow row = sheet.createRow(0);
XSSFCell cell = row.createCell(0);
final CTCellImpl ctCell = (CTCellImpl) cell.getCTCell();
ctCell.setT(STCellType.N);
ctCell.setV("");
Thanks in advance!

This is a known bug in older POI versions, see: https://bz.apache.org/bugzilla/show_bug.cgi?id=56702
It's been fixed since 3.11 version
Thank you all for your help!!

How to get the Excel sheet cell data by column name in using apache POI library

I want to get the cell data of a particular sheet with column name rather than column index,
Currently i can get the cell data using
fis = new FileInputStream(ExcelPath);
wb = new XSSFWorkbook(fis);
sh = wb.getSheet(SheetName);
cell = sh.getRow(rownum).getCell(colnum);
but I am looking for a way where I can get the cell data by,
cell = sh.getRow(rownum).getCell(ColName); //not working

Excel columns don't have names. They only have letters, eg A, D, BB
To work out how to map an Excel-style column letter into a POI-style 0-based index, you need to use the method convertColStringToIndex(java.lang.String ref) which does it for you
If you mean you want to lookup a column based on the value held in the first row, you should do something like:
DataFormatter fmt = new DataFormatter();
Map<String,Integer> headings = new HashMap<String,Integer>();
Row headings = sheet.getRow(0);
if (headings == null) throw new IllegalArgumentException("Empty headings row");
for (Cell c : headings) {
headings.put(fmt.formatCellValue(c), c.getColumnIndex());
}
If you have more complex use cases, such as a heading running over multiple rows, you'll need to write more complex code... It's all driven by your use-case

How to do Excel's "Convert to Number" in Java

I am reading data from Excel using Apache POI. I want to convert some cells to number while reading in Java as following:
Input 01.0234500
Output 1.02345
Input 412206362371
Output 4.12206E+11
Input 1234.201400002345
Output 1234.2014
When I am using "Convert to Number" in Excel, it works fine. But I want the same output while reading Excel cells in Java.
It can also be achieved using =VALUE() function in Excel. But how do I implement the same functionality in Java?

I think there are a number of ways to accomplish what you stipulate, but the most direct method is just to use the VALUE() function and then evaluate it. This certainly is not the most efficient method, but it works.
Essentially we just read in the value of the input cell, then create a new cell formula cell which contains the VALUE() function with the original value as the parameter. After that we call evalutateInCell to evaluate the VALUE() function and replace the cell value with the results.
XSSFWorkbook wb = new XSSFWorkbook();
XSSFSheet sheet = wb.createSheet("test");
Row row = sheet.createRow(0);
Cell inCell = row.createCell(0);
inCell.setCellValue("01.0234500");
Cell outCell = row.createCell(1);
FormulaEvaluator fev = wb.getCreationHelper().createFormulaEvaluator();
String value = inCell.getStringCellValue();
outCell.setCellFormula("VALUE(" + value + ")");
fev.evaluateInCell(outCell);
You can use the same method to replace the contents of the original cell if that is your preference.

This worked for me
new BigDecimal(cell.getNumericCellValue()).toPlainString()

Apache POI Excel - how to configure columns to be expanded?

I am using Apache POI API to generate excel spreadsheet to output some data.
The problem I am facing is when the spreadsheet is created and opened, columns are not expanded so that some long text like Date formatted text is not showing up on first glance.
I could just double click the column border in excel to expand or drag the border to adjust the column width but there could be 20+ columns and there is no way I want to do that manually every time I open the spreadsheet :(
I found out (though could be wrong method) groupRow() and setColumnGroupCollapsed() might be able to do the trick but no luck. Maybe I'm using it in wrong way.
Sample Code snippet
Workbook wb = new HSSFWorkbook();
CreationHelper createHelper = wb.getCreationHelper();
//create sheet
Sheet sheet = wb.createSheet("masatoSheet");
//not really working yet.... :(
//set group for expand/collapse
//sheet.groupRow(0, 10); //just random fromRow toRow argument values...
//sheet.setColumnGroupCollapsed(0, true);
//create row
Row row = sheet.createRow((short)0);
//put a cell in the row and store long text data
row.createCell(0).setCellValue("Loooooooong text not to show up first");
When this spreadsheet is created, the "Looooooong text not to show up first" string is in the cell but since the column is not expanded only "Loooooooo" is showing up.
How can I configure it so that when I open my spreadsheet, the column is already expanded???

After you have added all your data to the sheet, you can call autoSizeColumn(int column) on your sheet to autofit the columns to the proper size
Here is a link to the API.
See this post for more reference
Problem in fitting the excel cell size to the size of the content when using apache poi

Tip : To make Auto size work , the call to sheet.autoSizeColumn(columnNumber) should be made after populating the data into the excel.
Calling the method before populating the data, will have no effect.

If you want to auto size all columns in a workbook, here is a method that might be useful:
public void autoSizeColumns(Workbook workbook) {
int numberOfSheets = workbook.getNumberOfSheets();
for (int i = 0; i < numberOfSheets; i++) {
Sheet sheet = workbook.getSheetAt(i);
if (sheet.getPhysicalNumberOfRows() > 0) {
Row row = sheet.getRow(sheet.getFirstRowNum());
Iterator<Cell> cellIterator = row.cellIterator();
while (cellIterator.hasNext()) {
Cell cell = cellIterator.next();
int columnIndex = cell.getColumnIndex();
sheet.autoSizeColumn(columnIndex);
}
}
}
}

You can try something like this:
HSSFSheet summarySheet = wb.createSheet();
summarySheet.setColumnWidth(short column, short width);
Here params are:column number in sheet and its width
But,the units of width are pretty small, you can try 4000 for example.

For Excel POI:
sheetName.autoSizeColumn(cellnum);

sample code below
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("your sheet name");
HSSFRow row = sheet.createRow(0);
cell = row.createCell(0);
cell.setCellValue("A BIG NAME WITH AUTO SIZE FEATURE ENABLED");
//this is crucial
sheet.autoSizeColumn(0);
//argument must be cell number
cell = row.createCell(1);
cell.setCellValue("a big name without auto size feature enabled");
Check the output and go nuts :)

If you know the count of your columns (f.e. it's equal to a collection list). You can simply use this one liner to adjust all columns of one sheet (if you use at least java 8):
IntStream.range(0, columnCount).forEach(sheet::autoSizeColumn)

You can add this, after your loop.
for (int i = 0; i<53;i++) {
sheet.autoSizeColumn(i);
}

I use below simple solution:
This is your workbook and sheet:
XSSFWorkbook workbook = new XSSFWorkbook();
XSSFSheet sheet = workbook.createSheet("YOUR Workshhet");
then add data to your sheet with columns and rows. Once done with adding data to sheet write following code to autoSizeColumn width.
for (int columnIndex = 0; columnIndex < 15; columnIndex++) {
sheet.autoSizeColumn(columnIndex);
}
Here, instead 15, you add the number of columns in your sheet.
Hope someone helps this.

You can use setColumnWidth() if you want to expand your cell more.

Its very simple, use this one line code
dataSheet.autoSizeColumn(0)
or give the number of column in bracket
dataSheet.autoSizeColumn(cell number )

You can wrap the text as well. PFB sample code:
CellStyle wrapCellStyle = new_workbook.createCellStyle();
wrapCellStyle.setWrapText(true);