Modificar un excel o habrir un excel en java

1. Instalacion

Download the Java Excel library from the webpage http://jexcelapi.sourceforge.net/

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. Crear una hoja en excel

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".