The code below check if the first cell of an Excel file contains a date value. In Excel the cell type for date is returned as HSSFCell.CELL_TYPE_NUMERIC, to make sure if it contains a date we can use a utility method DateUtil.isCellDateFormatted(Cell cell), this method will check if the cell value is a valid date.

package org.kodejava.poi;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.CellType;
import org.apache.poi.ss.usermodel.DateUtil;

import java.io.FileInputStream;
import java.io.FileNotFoundException;

public class DateCellType {
    public static void main(String[] args) throws Exception {
        String filename = "datecelltype.xls";

        try (FileInputStream fis = new FileInputStream(filename)) {
            HSSFWorkbook workbook = new HSSFWorkbook(fis);
            HSSFSheet sheet = workbook.getSheetAt(0);

            // Read a cell the first cell on the sheet.
            HSSFCell cell = sheet.getRow(0).getCell(0);
            if (cell.getCellType() == CellType.NUMERIC) {
                System.out.println("Cell type for date data type is numeric.");
            }

            // Using HSSFDateUtil to check if a cell contains a date.
            if (DateUtil.isCellDateFormatted(cell)) {
                System.out.println("The cell contains a date value: "
                        + cell.getDateCellValue());
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
}

The example result of the code snippet:

Cell type for date data type is numeric.
The cell contains a date value: Fri Oct 08 00:00:00 CST 2021

Maven Dependencies

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>5.2.5</version>
</dependency>

In this example we try to obtain the Excel’s cell data type so that we can read the value using the right method. The data to be read is in a file named celltype.xls. The matrix below depict how the file is.

    |   COL
ROW |   0       1   2   3   4
----|-------------------------
0   |   1       2   A   B   TRUE
1   |   FALSE   X   Y   Z   10

package org.kodejava.poi;

import org.apache.poi.hssf.usermodel.HSSFCell;
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;
import org.apache.poi.ss.usermodel.CellType;
import org.apache.poi.ss.usermodel.Row;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.Iterator;

public class ObtainingCellType {

    public static void main(String[] args) throws Exception {
        String filename = "celltype.xls";

        try (FileInputStream fis = new FileInputStream(filename)) {
            HSSFWorkbook workbook = new HSSFWorkbook(fis);
            HSSFSheet sheet = workbook.getSheetAt(0);

            Iterator<Row> rows = sheet.rowIterator();
            while (rows.hasNext()) {
                HSSFRow row = (HSSFRow) rows.next();

                Iterator<Cell> cells = row.cellIterator();
                while (cells.hasNext()) {
                    HSSFCell cell = (HSSFCell) cells.next();

                    CellType type = cell.getCellType();
                    if (type == CellType.STRING) {
                        System.out.printf("[%d, %d] = STRING; Value = %s%n",
                                cell.getRowIndex(), cell.getColumnIndex(),
                                cell.getRichStringCellValue().toString());
                    } else if (type == CellType.NUMERIC) {
                        System.out.printf("[%d, %d] = NUMERIC; Value = %f%n",
                                cell.getRowIndex(), cell.getColumnIndex(),
                                cell.getNumericCellValue());
                    } else if (type == CellType.BOOLEAN) {
                        System.out.printf("[%d, %d] = BOOLEAN; Value = %b%n",
                                cell.getRowIndex(), cell.getColumnIndex(),
                                cell.getBooleanCellValue());
                    } else if (type == CellType.BLANK) {
                        System.out.printf("[%d, %d] = BLANK CELL%n",
                                cell.getRowIndex(), cell.getColumnIndex());
                    }
                }
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
}

Our program iterates the Excel file rows and cells and produce the following
output:

[0, 0] = NUMERIC; Value = 1.000000
[0, 1] = NUMERIC; Value = 2.000000
[0, 2] = STRING; Value = A
[0, 3] = STRING; Value = B
[0, 4] = BOOLEAN; Value = true
[1, 0] = BOOLEAN; Value = false
[1, 1] = STRING; Value = X
[1, 2] = STRING; Value = Y
[1, 3] = STRING; Value = Z
[1, 4] = NUMERIC; Value = 10.000000

Maven Dependencies

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>5.2.5</version>
</dependency>

In this example we demonstrate how to read data from an Excel file. In this example we limit to read a string data only. After reading the data, iterating each row and cells of the Excel file we display the content to the program console.

package org.kodejava.poi;

import org.apache.poi.hssf.usermodel.HSSFCell;
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;
import org.apache.poi.ss.usermodel.Row;

import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class ExcelReadExample {

    public static void main(String[] args) {
        // Excel file name. You can create a file name with a full
        // path information.
        String filename = "data.xls";

        // Create an ArrayList to store the data read from Excel sheet.
        List<List<HSSFCell>> sheetData = new ArrayList<>();

        try (FileInputStream fis = new FileInputStream(filename)) {
            // Create an Excel workbook from the file system.
            HSSFWorkbook workbook = new HSSFWorkbook(fis);
            // Get the first sheet on the workbook.
            HSSFSheet sheet = workbook.getSheetAt(0);

            // When we have a sheet object in hand we can iterator on
            // each sheet's rows and on each row's cells. We store the
            // data read on an ArrayList so that we can print the
            // content of the Excel to the console.
            Iterator<Row> rows = sheet.rowIterator();
            while (rows.hasNext()) {
                HSSFRow row = (HSSFRow) rows.next();
                Iterator<Cell> cells = row.cellIterator();

                List<HSSFCell> data = new ArrayList<>();
                while (cells.hasNext()) {
                    HSSFCell cell = (HSSFCell) cells.next();
                    data.add(cell);
                }
                sheetData.add(data);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

        showExcelData(sheetData);
    }

    private static void showExcelData(List<List<HSSFCell>> sheetData) {
        // Iterates the data and print it out to the console.
        for (List<HSSFCell> data : sheetData) {
            for (HSSFCell cell : data) {
                System.out.println(cell);
            }
        }
    }
}

Our program above print out the following lines:

AAAAAAAAAA
BBBBBBBBBB
CCCCCCCCCC
DDDDDDDDDD
EEEEEEEEEE
FFFFFFFFFF
GGGGGGGGGG
HHHHHHHHHH
IIIIIIIIII
JJJJJJJJJJ

Maven Dependencies

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>5.2.5</version>
</dependency>