This article demonstrate how to create and how to read Excel files with the Java Excel API.

1. Installation

Download the Java Excel library from the webpage

To use this library in your Java program add the lib jxl.jar to your classpath in your project. See Changing classpath in Eclipse.

2. Create an Excel Spreadsheet

Create a new Java project called de.vogella.java.excel. Create the de.vogella.java.excel.writer package and the following class.

package writer;

import java.io.File;
import java.io.IOException;
import java.util.Locale;

import jxl.CellView;
import jxl.Workbook;
import jxl.WorkbookSettings;
import jxl.format.UnderlineStyle;
import jxl.write.Formula;
import jxl.write.Label;
import jxl.write.Number;
import jxl.write.WritableCellFormat;
import jxl.write.WritableFont;
import jxl.write.WritableSheet;
import jxl.write.WritableWorkbook;
import jxl.write.WriteException;
import jxl.write.biff.RowsExceededException;


public class WriteExcel {

    private WritableCellFormat timesBoldUnderline;
    private WritableCellFormat times;
    private String inputFile;

public void setOutputFile(String inputFile) {
    this.inputFile = inputFile;
    }

    public void write() throws IOException, WriteException {
        File file = new File(inputFile);
        WorkbookSettings wbSettings = new WorkbookSettings();

        wbSettings.setLocale(new Locale("en", "EN"));

        WritableWorkbook workbook = Workbook.createWorkbook(file, wbSettings);
        workbook.createSheet("Report", 0);
        WritableSheet excelSheet = workbook.getSheet(0);
        createLabel(excelSheet);
        createContent(excelSheet);

        workbook.write();
        workbook.close();
    }

    private void createLabel(WritableSheet sheet)
            throws WriteException {
        // Lets create a times font
        WritableFont times10pt = new WritableFont(WritableFont.TIMES, 10);
        // Define the cell format
        times = new WritableCellFormat(times10pt);
        // Lets automatically wrap the cells
        times.setWrap(true);

        // create create a bold font with unterlines
        WritableFont times10ptBoldUnderline = new WritableFont(
                WritableFont.TIMES, 10, WritableFont.BOLD, false,
                UnderlineStyle.SINGLE);
        timesBoldUnderline = new WritableCellFormat(times10ptBoldUnderline);
        // Lets automatically wrap the cells
        timesBoldUnderline.setWrap(true);

        CellView cv = new CellView();
        cv.setFormat(times);
        cv.setFormat(timesBoldUnderline);
        cv.setAutosize(true);

        // Write a few headers
        addCaption(sheet, 0, 0, "Header 1");
        addCaption(sheet, 1, 0, "This is another header");


    }

    private void createContent(WritableSheet sheet) throws WriteException,
            RowsExceededException {
        // Write a few number
        for (int i = 1; i < 10; i++) {
            // First column
            addNumber(sheet, 0, i, i + 10);
            // Second column
            addNumber(sheet, 1, i, i * i);
        }
        // Lets calculate the sum of it
        StringBuffer buf = new StringBuffer();
        buf.append("SUM(A2:A10)");
        Formula f = new Formula(0, 10, buf.toString());
        sheet.addCell(f);
        buf = new StringBuffer();
        buf.append("SUM(B2:B10)");
        f = new Formula(1, 10, buf.toString());
        sheet.addCell(f);

        // now a bit of text
        for (int i = 12; i < 20; i++) {
            // First column
            addLabel(sheet, 0, i, "Boring text " + i);
            // Second column
            addLabel(sheet, 1, i, "Another text");
        }
    }

    private void addCaption(WritableSheet sheet, int column, int row, String s)
            throws RowsExceededException, WriteException {
        Label label;
        label = new Label(column, row, s, timesBoldUnderline);
        sheet.addCell(label);
    }

    private void addNumber(WritableSheet sheet, int column, int row,
            Integer integer) throws WriteException, RowsExceededException {
        Number number;
        number = new Number(column, row, integer, times);
        sheet.addCell(number);
    }

    private void addLabel(WritableSheet sheet, int column, int row, String s)
            throws WriteException, RowsExceededException {
        Label label;
        label = new Label(column, row, s, times);
        sheet.addCell(label);
    }

    public static void main(String[] args) throws WriteException, IOException {
        WriteExcel test = new WriteExcel();
        test.setOutputFile("c:/temp/lars.xls");
        test.write();
        System.out
                .println("Please check the result file under c:/temp/lars.xls ");
    }
}

I assume that the code is pretty much self-explaining. I tried to add lots of comments to make it easier to understand.For more complex examples have a look at the excellent documentation of the Java Excel API which is also part of the distribution.

3. Read an existing Excel Spreadsheet

Reuse the project "de.vogella.java.excel". Create a package "de.vogella.java.excelreader" and the following class "ReadExcel".

package reader;

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

import jxl.Cell;
import jxl.CellType;
import jxl.Sheet;
import jxl.Workbook;
import jxl.read.biff.BiffException;

public class ReadExcel {

    private String inputFile;

    public void setInputFile(String inputFile) {
        this.inputFile = inputFile;
    }

    public void read() throws IOException  {
        File inputWorkbook = new File(inputFile);
        Workbook w;
        try {
            w = Workbook.getWorkbook(inputWorkbook);
            // Get the first sheet
            Sheet sheet = w.getSheet(0);
            // Loop over first 10 column and lines

            for (int j = 0; j < sheet.getColumns(); j++) {
                for (int i = 0; i < sheet.getRows(); i++) {
                    Cell cell = sheet.getCell(j, i);
                    CellType type = cell.getType();
                    if (type == CellType.LABEL) {
                        System.out.println("I got a label "
                                + cell.getContents());
                    }

                    if (type == CellType.NUMBER) {
                        System.out.println("I got a number "
                                + cell.getContents());
                    }

                }
            }
        } catch (BiffException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws IOException {
        ReadExcel test = new ReadExcel();
        test.setInputFile("c:/temp/lars.xls");
        test.read();
    }

}

Create an excel spreadsheet and save it somewhere, e.g. c:/temp/lars.xls.

I assume that the code is pretty much self-explaining. I tried to add lots of comments to make it easier to understand.For more complex examples have a look at the excellent documentation of the Java Excel API which is also part of the distribution.

4. Links and Literature