Exporting JTable data to Excel

Recently I wanted to find a way to export JTable data to Excel. I found an excellent example of how to do this in Swing Hacks by Joshusa Marinacci and Chris Adamson. The authors show an example of saving JTable data to a tab delimited file with a ".xls" extension. The file can then be opened by Excel and converted to a spreadsheet.

I liked their approach, but I also wanted to provide the capability to launch Excel with the file opened in it as I've seen in other applications. So, I added some code to create a JPopupMenu component with options for saving the data or opening in Excel.

I also wanted to keep Excel from converting product numbers (specifically ISBN numbers) to numeric data in the spreadsheet. The reason for this is that leading zeros can be part of an ISBN.

My example along with the Marinaccci's and Admanson's JTable to Excel code follows. One caveat, I offer no explanation of the authors' code. After all, it's in their book. For a complete explanation see Swing Hacks. It is an excellent book full of tricks that every Swing developer should have.

Enjoy.

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;
import java.io.*;
import javax.swing.table.*;


public class ExcelTest {

 /**
  * @param args
  */
 public static void main(String[] args) {
//  An array of book titles and their associated ISBN numbers
  String [][] data = {
    {"Summerall","0785214925"},
    {"The Secret Message of Jesus","084990000X"},
    {"Buck Wild","159555064X"},
    {"25 Ways to Win with People","0785260943"},
    {"Aesop and the CEO ","0785260102"},
    {"ALL Business is Show Business ","0785206086"},
    {"Becoming A Person of Influence","0785271007"},
    {"Checklist for Life for Leaders","0785260013"},
    {"Duct Tape Marketing ","078522100X"},
    {"38 Values to Live By ","0849916631"},
    {"Blue Moon","0785260641"},
    {"Blue Like Jazz ","9780785263708"},
    {"Wild at Heart ","0785262989"},
    {"Wild Men, Wild Alaska ","078521772X "},
    {"The Duct Tape Bible, NCV","0718018249"}
  };
  String [] headers = {"Title","ISBN"};
  final JFrame frame = new JFrame("JTable to Excel Hack");
  DefaultTableModel model = new DefaultTableModel(data,headers);
  final JTable table = new JTable(model);
  JScrollPane scroll = new JScrollPane(table);

//  my JPopupMenu component
  final JPopupMenu popup = new JPopupMenu();

//  the save JMenuItem and its associated ActionListener
  JMenuItem save = new JMenuItem("save to file");
  save.addActionListener(new
    ActionListener() {
   public void actionPerformed(ActionEvent action){
    try {
     ExcelExporter exp = new ExcelExporter();
     exp.exportTable(table, new File("results.xls"));
    }
    catch (IOException ex) {
     System.out.println(ex.getMessage());
     ex.printStackTrace();
    }
   }
  });
  popup.add(save);

//  The open JMenuItem and its associated ActionListener
  JMenuItem open = new JMenuItem("open in Excel");
  open.addActionListener(new
    ActionListener() {
   public void actionPerformed(ActionEvent action){
    try {
//     Note that i'm actually saving the file first
     ExcelExporter exp = new ExcelExporter();
     File file = new File("results1.xls");
     exp.exportTable(table, file);
     ExcelOpener opn = new ExcelOpener();
     opn.openTable(file);
    }
    catch (IOException ex) {
     System.out.println(ex.getMessage());
     ex.printStackTrace();
    }

   }
  });
  popup.add(open);

//  the following method only works in JDK 5.0 or greater
//  table.setComponentPopupMenu(popup);

  JLabel label1 = new JLabel("Right Click to Export Data...", JLabel.CENTER);

//  the following code is needed for JDK 1.4
  table.addMouseListener(new MouseAdapter() {
   public void mousePressed(MouseEvent event){
    if(popup.isPopupTrigger(event)){
     popup.show(event.getComponent(), event.getX(),event.getY());
    }
   }
   public void mouseReleased(MouseEvent event){
    if(popup.isPopupTrigger(event)){
     popup.show(event.getComponent(), event.getX(),event.getY());
    }
   }
  });

  frame.getContentPane().add("Center",scroll);
  frame.getContentPane().add("South",label1);
  frame.pack();
  frame.setVisible(true);
 }
}
class ExcelExporter {
 public ExcelExporter() {}
 public void exportTable(JTable table, File file) throws IOException {
  TableModel model = table.getModel();
  FileWriter out = new FileWriter(file);

  for(int i=0; i < model.getColumnCount();i++) {
   out.write(model.getColumnName(i)+"\t");
 }
 out.write("\n");
 
 for(int i=0; i < model.getRowCount();i++){
  for(int j=0;j < model.getColumnCount();j++){
//   I added this check for the ISBN conversion
   if(j==0) {
//    the book Title
    out.write(model.getValueAt(i,j).toString() + "\t");
   } else {
/*
the ISBN Number
Note that I added a \" to the front of the string
and a \t followed by a closing \" to let Excel know
that this field is to be converted as text
     */
    out.write("\""+model.getValueAt(i, j).toString()+"\t"+"\"");
   }
  }
  out.write("\n");
 }
 out.close();
 System.out.println("write to " + file);
}
}
class ExcelOpener {
 public ExcelOpener() {}
 public void openTable(File file) throws IOException {
  Runtime run = Runtime.getRuntime();
//  I make the assumption that the client has Excel and
//  the file type .XLS is associated with Excel

//  This is a simple check to find out the operating system
  String lcOSName = System.getProperty("os.name").toLowerCase();
  boolean MAC_OS_X = lcOSName.startsWith("mac os x");
  if(MAC_OS_X){
   run.exec("open "+ file);
  } else {
   run.exec("cmd.exe /c start " + file);
  }
  System.out.println(file + " opened");
 }
}