Get each cells data from Excel converted to XML to stored to DB

Question

After looking for some resources, I could load an Excel file which contain 1.000.000 rows data. But, I did not know how to get each data. Here is my code so far...

public void create(MultipartFile file) throws Exception {
    try {
        InputStream fileStream = new BufferedInputStream(file.getInputStream());
        OPCPackage opc = OPCPackage.open(fileStream);
        XSSFReader xssf = new XSSFReader(opc);
        SharedStringsTable sst = xssf.getSharedStringsTable();
        XSSFReader.SheetIterator itr = (XSSFReader.SheetIterator)xssf.getSheetData();

// I just realize, if I running below for-loop,
// this only print strings and in random order, not in the same order as the excel file.
// 20 is just an example

        for (int i = 0; i < 20; i++) {
            System.out.println(sst.getEntryAt(i).getT().toString());
        }

        while (itr.hasNext()) {
            InputStream is = itr.next();
            if (itr.getSheetName().equals("MY_SHEET_NAME")) {
                while ("data is avaiable, this is just example, I'll use something like hasNext() for the row in the sheet, but I dont know how to do it" != null) {
                    // Want to process and get all data in each cells, then store to DB
                    // What I did not know, is how to get data in each cells
                }
            } else {
                throw new Exception("Sheet not found");
            }
        }
    } catch (Exception e) {
        throw new Exception("Error is: " + e.getMessage());
    } finally {
        if (is != null) {
            is.close();
        }

        if (opc != null){
            opc.close();
        }

        if (fileStream != null) {
            fileStream.close();
        }
    }
}

I've tried to look at here to process the sheet, but I did not get how to grab the data in each cells. Any help will really help me..

Update

if I read the doc of apache POI, here , from the link, code part that will process my excel is here:

public void processOneSheet(String filename) throws Exception {
        OPCPackage pkg = OPCPackage.open(filename);
        XSSFReader r = new XSSFReader( pkg );
        SharedStringsTable sst = r.getSharedStringsTable();

        XMLReader parser = fetchSheetParser(sst);

        // To look up the Sheet Name / Sheet Order / rID,
        //  you need to process the core Workbook stream.
        // Normally it's of the form rId# or rSheet#
        InputStream sheet2 = r.getSheet("rId2");
        InputSource sheetSource = new InputSource(sheet2);
        parser.parse(sheetSource);
        sheet2.close();
    }

But, after call parser.parse(sheetSource) , how I could get each data from each row and column? Because I wanna do validation on each data on each cells, then store it to database.

Update 2 I've try using this answer, https://stackoverflow.com/a/51818500/10454516 . I could get the data, I've try to insert myObjectRepo.save(result) or myObjectRepo.save(myObject), both I placed the code inside void endRow method and I also try to place it right after switch but inside the if(lineNumber > 0), but its always return NullPointerException. But if I did not call save method, I try to print the result in the console, the result is printed.

Answer 1

One of the way you could grab the excel data is :

try {
        InputStream excelFile = new FileInputStream(mFileName); 
        XSSFWorkbook wb = new XSSFWorkbook(excelFile);
        XSSFSheet sheet = wb.getSheetAt(0);
        XSSFRow row;
        XSSFCell cell;

        Iterator<Row> rows = sheet.rowIterator();

        int col = 0, colPR = 1;
        int pageRank = 0;
        String url = null;

        while (rows.hasNext()) {
            row = (XSSFRow) rows.next();
            url = row.getCell(col).getStringCellValue();

            System.out.println("--------------------------");
        }

        FileOutputStream out = new FileOutputStream(mFileName);
        wb.write(out);
        out.flush();
        out.close();
    }
    catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

Answer 2

Well, I'd like to answer my own question. After several experiments/trials and also based on this answer , I've made it to upload excel file which has at least 1.000.000 rows data and stored into db (postgresql). For upload, read and insert 1.000.000 rows data needs 5 minutes. Here is the link to the project . Hope this could help anybody who need it.