XLSX removing sheets OutOfMemory Exception - apache-poi

Question

I am trying to load the XLSX file using POI library that has 5 sheets. Size of the file is 5 MB. Total records in all sheets are around 30,000.
Once the file is loaded i need to delete the 1 or more sheets on the fly based on sheet neame as input.
Here is the snippet.
public void generateReportWorkBook(String[] requestedReports) throws Exception {
// Read the file
String dailyTicketReport = ReportConstants.REPORT_PATH + ReportConstants.FILE_NAME + ReportConstants.XLSX_FILE_EXTN;
FileInputStream fis = null;
XSSFWorkbook book = null;
try {
fis = new FileInputStream(dailyTicketReport);
book = new XSSFWorkbook(fis);
for (int i = book.getNumberOfSheets() - 1; i >= 0; i--) {
XSSFSheet tmpSheet = book.getSheetAt(i);
if (!ArrayUtils.contains(requestedReports, tmpSheet.getSheetName())) {
book.removeSheetAt(i);
}
}
} catch (Exception e) {
logger.error("Error occured while removing the sheets from workbook");
throw e;
} finally {
IOUtils.closeQuietly(fis);
}
}
When i execute the program. I get OutofMemory Exception.
How can i remove the sheets without memory issue.

Answer 1

I too faced the same issue of OOM while parsing xlsx file...after two days of struggle, I finally found out the below code that was really perfect;
This code is based on sjxlsx. It reads the xlsx and stores in a HSSF sheet.
// read the xlsx file
SimpleXLSXWorkbook = new SimpleXLSXWorkbook(new File("C:/test.xlsx"));
HSSFWorkbook hsfWorkbook = new HSSFWorkbook();
org.apache.poi.ss.usermodel.Sheet hsfSheet = hsfWorkbook.createSheet();
Sheet sheetToRead = workbook.getSheet(0, false);
SheetRowReader reader = sheetToRead.newReader();
Cell[] row;
int rowPos = 0;
while ((row = reader.readRow()) != null) {
org.apache.poi.ss.usermodel.Row hfsRow = hsfSheet.createRow(rowPos);
int cellPos = 0;
for (Cell cell : row) {
if(cell != null){
org.apache.poi.ss.usermodel.Cell hfsCell = hfsRow.createCell(cellPos);
hfsCell.setCellType(org.apache.poi.ss.usermodel.Cell.CELL_TYPE_STRING);
hfsCell.setCellValue(cell.getValue());
}
cellPos++;
}
rowPos++;
}
return hsfSheet;