I'm trying to do my first tests of reading large xlsx file with POI, but to do a simple test with a small file I fail to show the value of a cell.
Someone can tell me what is my mistake. All the suggestions are welcome. Thanks.
Test.java:
import java.io.File;
import java.io.FileInputStream;
import org.apache.poi.openxml4j.opc.OPCPackage;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
public class Test {
public static void main(String[] args) throws Throwable {
File file = new File("/tmp/test.xlsx");
OPCPackage pkg = OPCPackage.open(new FileInputStream(file.getAbsolutePath()));
XSSFWorkbook xssfwb = new XSSFWorkbook(pkg);
SXSSFWorkbook wb = new SXSSFWorkbook(xssfwb, 100);
Sheet sh = wb.getSheet("Hola");
System.out.println("Name: "+sh.getSheetName()); // Line 19
System.out.println("Val: "+sh.getRow(1).getCell(1).getStringCellValue()); // Line 20
}
}
Result:
Name: Hola
Exception in thread "main" java.lang.NullPointerException
at Test.main(Test.java:20)
test.xlsx:
Please consult: similar question SXSSFWorkBook is write only, it doesn't support reading.
For low memory reading of .xlsx files, you should look at the XSSF and SAX EventModel documentation : Gagravarr
If memory wouldn't be an issue you could use a XSSFSheet instead eg
File file = new File("D:/temp/test.xlsx");
FileInputStream fis = new FileInputStream(file);
XSSFWorkbook wb = new XSSFWorkbook(fis);
XSSFSheet sh = wb.getSheet("Hola");
System.out.println(sh.getLastRowNum());
System.out.println("Name: "+sh.getSheetName());
Row row = sh.getRow(1);
System.out.println(row.getRowNum());
System.out.println("Val: "+sh.getRow(1).getCell(1).getStringCellValue());
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;
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