Re: HSSF

From:
"John B. Matthews" <nospam@nospam.invalid>
Newsgroups:
comp.lang.java.help
Date:
Wed, 13 May 2009 06:26:42 -0400
Message-ID:
<nospam-878AA0.06264113052009@news.aioe.org>
In article
<34adced1-4b01-4a3e-9f56-e55e46de37f1@b1g2000vbc.googlegroups.com>,
 dendeezen <tsd35328@scarlet.be> wrote:
[...]

I am a novice and try to understand how HSSF works.

When I try to read an excel cell that is not empty, it works fine as
far as the content is not a date, in which case I get an number back.

When I try to read an empty cell , I get the exception: Exception in
thread "main" java.lang.NullPointerException at
com.ms.util.POIExcelReader.main(POIExcelReader.java:37)

[...]

         HSSFCell cel = rij.getCell((short) 4); // this cell is empty

This method is deprecated. Empty cells are null and should not be
dereferenced. Another approach is to use the supplied iterator(), which
skips empty cells:

<code>
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFDateUtil;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;

public class POIExcelReader {

    public static void main(String[] args) throws IOException {
        InputStream myxls = new FileInputStream("test.xls");
        HSSFWorkbook book = new HSSFWorkbook(myxls);
        HSSFSheet sheet = book.getSheetAt(0);
        HSSFRow row = sheet.getRow(2);
        for (Cell cell : row) {
            printCell(cell);
        }
    }

    private static void printCell(Cell cell) {
        switch (cell.getCellType()) {
            case HSSFCell.CELL_TYPE_BLANK:
                System.out.println("EMPTY");
                break;
            case HSSFCell.CELL_TYPE_STRING:
                System.out.println(cell.getStringCellValue());
                break;
            case HSSFCell.CELL_TYPE_NUMERIC:
                if (HSSFDateUtil.isCellDateFormatted(cell)) {
                    System.out.println(cell.getDateCellValue());
                } else {
                    System.out.println(cell.getNumericCellValue());
                }
                break;
            case HSSFCell.CELL_TYPE_BOOLEAN:
                System.out.println(cell.getBooleanCellValue());
                break;
            case HSSFCell.CELL_TYPE_FORMULA:
                System.out.println(cell.getCellFormula());
                break;
            default:
                System.out.println("DEFAULT");
        }
    }
}
</code>

<console>
Tue May 13 00:00:00 EDT 2009
123.0
ABCabc
true
3+3
</console>

--
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>

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