Read xlsx file with POI (SXSSFWorkbook)

Question

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:

Answer 1

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 e.g.

    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());