Exporting JTable Data including Table Headers to Excel File

Question

I need help regarding this, I can't get it right. I want to export JTable data to excel file. There is no error but I am getting only the data it shows and does not include the table headers.

I am running this in a Netbeans 8.2 IDE and had also imported the essential jar files.

Data on my jtable is provided by my mysql database and I need to export it from jtable to an excel file. Anyway tblData is my JTable variable name.

private void btnExportActionPerformed(java.awt.event.ActionEvent evt) {                                          

        FileOutputStream excelFOS = null;
        BufferedOutputStream excelBOS = null;
        XSSFWorkbook wb = null;


        JFileChooser excelFileChooser = new JFileChooser();
        excelFileChooser.setDialogTitle("Save As");
        FileNameExtensionFilter fnef = new FileNameExtensionFilter("Excel Files","xls","xlsx","ods");
        excelFileChooser.setFileFilter(fnef);
        int excelChooser = excelFileChooser.showSaveDialog(null);

        if(excelChooser == JFileChooser.APPROVE_OPTION){

            try {
                wb = new XSSFWorkbook();
                XSSFSheet sheet = wb.createSheet("Data Sheet");

                for(int i = 0; i < tblData.getRowCount(); i++){
                    XSSFRow excelRow = sheet.createRow(i);
                    for(int j = 0; j < tblData.getColumnCount(); j++){

                        XSSFCell excelCell = excelRow.createCell(j);
                        excelCell.setCellValue(tblData.getValueAt(i, j).toString());

                    }
                }   

                excelFOS = new FileOutputStream(excelFileChooser.getSelectedFile() + ".xlsx");
                excelBOS = new BufferedOutputStream(excelFOS);
                wb.write(excelBOS);
                JOptionPane.showMessageDialog(null, "Successfully saved.");

            } catch (FileNotFoundException ex) {
                ex.printStackTrace();
            } catch (IOException ex) {
                ex.printStackTrace();
            } finally {
                try {
                    if(excelBOS != null){
                         excelBOS.close();
                    }
                    if(excelFOS != null){
                         excelFOS.close();
                    }
                    if(wb != null){
                         wb.close();
                    }
                } catch (IOException ex) {
                    ex.printStackTrace();
                }
            } //---- end finally
        } //---- end if condition
    }

I am expecting for the header to be exported. Can anyone help me with this.

Answer 1

Not really clear what tblData is in your provided code. But If I would have the requirement to export a JTable to Excel, then I would go by TableModel of the JTable. First write the column names to first row of the Excel sheet using TableModel.getColumnName. Then write the table data to next rows of the Excelsheet using TableModel.getValueAt.

Complete example:

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.io.FileOutputStream;

import javax.swing.JTable;
import javax.swing.table.TableModel;

class WriteJTableToExcel {

 static void exportToExcel(JTable table, String filePath) throws Exception {
  TableModel model = table.getModel();
  Workbook workbook = new XSSFWorkbook();
  Sheet sheet = workbook.createSheet();
  Row row;
  Cell cell;

  // write the column headers
  row = sheet.createRow(0);
  for (int c = 0; c < model.getColumnCount(); c++) {
   cell = row.createCell(c);
   cell.setCellValue(model.getColumnName(c));
  }

  // write the data rows
  for (int r = 0; r < model.getRowCount(); r++) {
   row = sheet.createRow(r+1);
   for (int c = 0; c < model.getColumnCount(); c++) {
    cell = row.createCell(c);
    Object value = model.getValueAt(r, c);
    if (value instanceof String) {
     cell.setCellValue((String)value);
    } else if (value instanceof Double) {
     cell.setCellValue((Double)value);
    }
   }
  }

  FileOutputStream out = new FileOutputStream(filePath);
  workbook.write(out);
  out.close();
  workbook.close();

 }

 public static void main(String[] args) throws Exception {

  Object columnNames[] = {"Name", "Amount", "Factor"};
  Object rowData[][] = {
   {"Bob", 12.0, 3.0},
   {"Alice", 34.0, 2.5},
   {"Jack", 56.0, 2.0},
   {"John", 78.0, 1.5}
  };
  JTable table = new JTable(rowData, columnNames);

  exportToExcel(table, "./Excel.xlsx");

 }
}

Answer 2

you need to export the getTableHeader() from your jTable separately before you export your data. It is not stored together with the data, as it is in an Excel workbook.
Hope that helps :-)