Dec 01

The following just puts together everything we’ve covered on POI so far.

The following is a simple utility method to read an Excel file (XLS or XLSX) and write the reference and contents of each cell to a writer of your choice. So you could use it to dump stdout, or a file.

public static void dump(File excel, PrintWriter out) throws IOException, InvalidFormatException {
	FileInputStream in = new FileInputStream(excel);
	Workbook workbook = WorkbookFactory.create(in);

	int nsheets = workbook.getNumberOfSheets();
	for (int i = 0; i < nsheets; i++) {
		Sheet sheet = workbook.getSheetAt(i);
		for (Row row : sheet) {
			for (Cell cell : row) {
				String cellValue = null;

				switch (cell.getCellType()) {
					case Cell.CELL_TYPE_STRING:
						cellValue = cell.getStringCellValue();
						break;

					case Cell.CELL_TYPE_FORMULA:
						cellValue = cell.getCellFormula();
						break;

					case Cell.CELL_TYPE_NUMERIC:
						if (DateUtil.isCellDateFormatted(cell)) {
							cellValue = 
								cell.getDateCellValue().toString();
						} else {
							cellValue = Double.toString(
								cell.getNumericCellValue());
						}
						break;

					case Cell.CELL_TYPE_BLANK:
						cellValue = "";
						break;

					case Cell.CELL_TYPE_BOOLEAN:
						cellValue = Boolean
								.toString(cell.getBooleanCellValue());
						break;
				}
				CellReference cellReference = new CellReference(
						row.getRowNum(), cell.getColumnIndex());
				out.println(cellReference.formatAsString()+"="+cellValue);
			}
		}
	}
	in.close();
}

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Nov 25

In previous posts we have covered opening Excel files, and accessing sheets. Now we need to move onto reading the rows and cells in that sheet.

FileInputStream in = new FileInputStream(file);
Workbook workbook = WorkbookFactory.create(in);

int nsheets = workbook.getNumberOfSheets();
for (int i=0; i<nsheets; i++) {
	Sheet sheet = workbook.getSheetAt(i);
	for (Row row : sheet) {
		for (Cell cell : row) {
			
			// Do what you want with the cell value
		}
	}
}

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Nov 23

POI supports the older OLE2 format Excel (XLS) files using HSSF, and using XSSF can also handle the newer OOXML format (XLSX) used by Microsoft Office 2007, 2008 and onwards.

If you want to open an Excel file in either format then you can use something like the following:

FileInputStream in = new FileInputStream(file);
Workbook workbook = WorkbookFactory.create(in);

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