How do I check if a cell contains a date value?

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 HSSFDateUtil.isCellDateFormatted(HSSFCell cell), this method will check if the cell value is a valid date.

package org.kodejava.example.poi;

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

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 (HSSFDateUtil.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: Tue Jul 23 00:00:00 WITA 2019

Maven Dependencies

<!-- https://search.maven.org/remotecontent?filepath=org/apache/poi/poi/4.1.0/poi-4.1.0.jar -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>4.1.0</version>
</dependency>

Maven Central

How do I obtain Excel’s cell data type?

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.example.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.CellType;

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 rows = sheet.rowIterator();
            while (rows.hasNext()) {
                HSSFRow row = (HSSFRow) rows.next();
                Iterator cells = row.cellIterator();
                while (cells.hasNext()) {
                    HSSFCell cell = (HSSFCell) cells.next();

                    CellType type = cell.getCellType();
                    if (type == CellType.STRING) {
                        System.out.println("[" + cell.getRowIndex() + ", "
                            + cell.getColumnIndex() + "] = STRING; Value = "
                            + cell.getRichStringCellValue().toString());
                    } else if (type == CellType.NUMERIC) {
                        System.out.println("[" + cell.getRowIndex() + ", "
                            + cell.getColumnIndex() + "] = NUMERIC; Value = "
                            + cell.getNumericCellValue());
                    } else if (type == CellType.BOOLEAN) {
                        System.out.println("[" + cell.getRowIndex() + ", "
                            + cell.getColumnIndex() + "] = BOOLEAN; Value = "
                            + cell.getBooleanCellValue());
                    } else if (type == CellType.BLANK) {
                        System.out.println("[" + cell.getRowIndex() + ", "
                            + cell.getColumnIndex() + "] = BLANK CELL");
                    }
                }
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
}

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

[0, 0] = NUMERIC; Value = 1.0
[0, 1] = NUMERIC; Value = 2.0
[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 = 10.0

Maven Dependencies

<!-- https://search.maven.org/remotecontent?filepath=org/apache/poi/poi/4.1.0/poi-4.1.0.jar -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>4.1.0</version>
</dependency>

Maven Central

How do I read Excel file?

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 the each rows and cells of the Excel file we display the content to the program console.

package org.kodejava.example.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 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) {
        // An 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 printed the
            // content of the excel to the console.
            Iterator rows = sheet.rowIterator();
            while (rows.hasNext()) {
                HSSFRow row = (HSSFRow) rows.next();
                Iterator 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

<!-- https://search.maven.org/remotecontent?filepath=org/apache/poi/poi/4.1.0/poi-4.1.0.jar -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>4.1.0</version>
</dependency>

Maven Central

How do I format cell style in Excel document?

This example demonstrate how to use HSSFCellStyle and HSSFFont to format the cell style in excel document. Using this class we can define cell border, foreground and background color. We can also define the font we use to display the cell value.

package org.kodejava.example.poi;

import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.hssf.util.HSSFColor;
import org.apache.poi.ss.usermodel.BorderStyle;
import org.apache.poi.ss.usermodel.FillPatternType;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

public class ExcelCellFormat {
    public static void main(String[] args) {
        // Create an instance of workbook and sheet
        HSSFWorkbook workbook = new HSSFWorkbook();
        HSSFSheet sheet = workbook.createSheet();

        // Create an instance of HSSFCellStyle which will be use to format the
        // cell. Here we define the cell top and bottom border and we also
        // define the background color.
        HSSFCellStyle style = workbook.createCellStyle();
        style.setBorderTop(BorderStyle.DOUBLE);
        style.setBorderBottom(BorderStyle.THIN);
        style.setFillForegroundColor(
            HSSFColor.HSSFColorPredefined.GREY_25_PERCENT.getIndex());
        style.setFillPattern(FillPatternType.SOLID_FOREGROUND);

        // We also define the font that we are going to use for displaying the
        // data of the cell. We set the font to ARIAL with 20pt in size and
        // make it BOLD and give blue as the color.
        HSSFFont font = workbook.createFont();
        font.setFontName(HSSFFont.FONT_ARIAL);
        font.setFontHeightInPoints((short) 20);
        font.setBold(true);
        font.setColor(HSSFColor.HSSFColorPredefined.BLUE.getIndex());
        style.setFont(font);

        // We create a simple cell, set its value and apply the cell style.
        HSSFRow row = sheet.createRow(1);
        HSSFCell cell = row.createCell(1);
        cell.setCellValue(new HSSFRichTextString("Hi there... It's me again!"));
        cell.setCellStyle(style);
        sheet.autoSizeColumn((short) 1);

        // Finally we write out the workbook into an excel file.
        try (FileOutputStream fos =
                 new FileOutputStream(new File("ExcelDemo.xls"))) {
            workbook.write(fos);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Maven Dependencies

<!-- https://search.maven.org/remotecontent?filepath=org/apache/poi/poi/4.1.0/poi-4.1.0.jar -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>4.1.0</version>
</dependency>

Maven Central

How do I create an Excel document using Apache POI?

This example demonstrate how to create an excel document using Apache POI library. In this example we create a simple document containing two sheets which have a value on their first cell.

package org.kodejava.example.poi;

import org.apache.poi.hssf.usermodel.*;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

public class CreateExcelDemo {
    public static void main(String[] args) {
        // Creating an instance of HSSFWorkbook.
        HSSFWorkbook workbook = new HSSFWorkbook();

        // Create two sheets in the excel document and name it First Sheet and
        // Second Sheet.
        HSSFSheet firstSheet = workbook.createSheet("FIRST SHEET");
        HSSFSheet secondSheet = workbook.createSheet("SECOND SHEET");

        // Manipulate the firs sheet by creating an HSSFRow which represent a
        // single row in excel sheet, the first row started from 0 index. After
        // the row is created we create a HSSFCell in this first cell of the row
        // and set the cell value with an instance of HSSFRichTextString
        // containing the words FIRST SHEET.
        HSSFRow rowA = firstSheet.createRow(0);
        HSSFCell cellA = rowA.createCell(0);
        cellA.setCellValue(new HSSFRichTextString("FIRST SHEET"));

        HSSFRow rowB = secondSheet.createRow(0);
        HSSFCell cellB = rowB.createCell(0);
        cellB.setCellValue(new HSSFRichTextString("SECOND SHEET"));

        // To write out the workbook into a file we need to create an output
        // stream where the workbook content will be written to.
        try (FileOutputStream fos = 
                 new FileOutputStream(new File("CreateExcelDemo.xls"))) {
            workbook.write(fos);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Maven Dependencies

<!-- https://search.maven.org/remotecontent?filepath=org/apache/poi/poi/4.1.0/poi-4.1.0.jar -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>4.1.0</version>
</dependency>

Maven Central