Java : netbean ช่วยแนะนำวิธี import file จาก excel ให้แสดง format วันที่ ทีครับ

package Modelo;
import java.io.*;
//import java.text.ParseException;
//import java.text.SimpleDateFormat;
import java.util.*;
import javax.swing.*;
//import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.xssf.usermodel.*;
//import java.text.ParseException;
//import java.text.SimpleDateFormat;
//import java.util.Date;

/**
 *
 * @author ricardo
 */
public class ModeloExcel {
    Workbook wb;
    
    /*class DateRenderer extends DefaultTableCellRenderer {

private static final long serialVersionUID = 1L;
private Date dateValue;
private SimpleDateFormat sdfNewValue = new SimpleDateFormat("dd/mm/yyyy");
private String valueToString = "";


public void setValue(Object value) {
    
    if ((value != null)) {
        String stringFormat = value.toString();
        try {
            dateValue = new SimpleDateFormat("dd/mm/yyyy", Locale.ENGLISH).parse(stringFormat);
        } catch (ParseException e) {
            e.printStackTrace();
        }
    }
    String pattern = "MM/dd/yyyy";
    SimpleDateFormat format = new SimpleDateFormat(pattern);
    valueToString = format.format(new Date());
    value = valueToString;
    super.setValue(value);
    
}
}*/
    public String Importar(File archivo, JTable tablaD){
        /*String pattern = "MM/dd/yyyy";
            SimpleDateFormat format = new SimpleDateFormat(pattern);
                                    
    try {
      Date date = format.parse("12/31/2006");
      System.out.println(date);
    } catch (ParseException e) {
      e.printStackTrace();
    }
    // formatting
    format.format(new Date());*/
        String respuesta="Import ไม่สำเร็จ";
        DefaultTableModel modeloT = new DefaultTableModel();
        tablaD.setModel(modeloT);
        try {
            wb = WorkbookFactory.create(new FileInputStream(archivo));
            Sheet hoja = wb.getSheetAt(0);
            Iterator filaIterator = hoja.rowIterator();
            int indiceFila=-1;
            while (filaIterator.hasNext()) {                
            indiceFila++;
            Row fila = (Row) filaIterator.next();
            Iterator columnaIterator = fila.cellIterator();
            Object[] listaColumna = new Object[6];
            int indiceColumna=-1;
            while (columnaIterator.hasNext()) {                    
                    indiceColumna++;
                    Cell cell = (Cell) columnaIterator.next();
                    /*if(cell.getCellType()==Cell.CELL_TYPE_NUMERIC){
        if (DateUtil.isCellDateFormatted(cell)) {
            System.out.println(cell.getDateCellValue());
        } else {
            System.out.println(cell.getNumericCellValue());
        }
}*/
                    if(indiceFila==0){
                        modeloT.addColumn(cell.getStringCellValue());
                    }else{
                        if(cell!=null){
                            switch(cell.getCellType()){
                                case Cell.CELL_TYPE_NUMERIC:
                                    listaColumna[indiceColumna]= (int)Math.round(cell.getNumericCellValue());
                                    break;
                                case Cell.CELL_TYPE_STRING:
                                    listaColumna[indiceColumna]= cell.getStringCellValue();
                                    break;
                                case Cell.CELL_TYPE_BOOLEAN:
                                    listaColumna[indiceColumna]= cell.getBooleanCellValue();
                                    break;
                                default:
                                    listaColumna[indiceColumna]=cell.getDateCellValue();
                                    break;
                            }
                        }
                    }
                }
                if(indiceFila!=0)modeloT.addRow(listaColumna);
            }
            
            respuesta="Import สำเร็จ";
        } catch (Exception e) {
            //JOptionPane.showMessageDialog(null, e.toString());

            
        }
        return respuesta;
    }
    
    public String Exportar(File archivo, JTable tablaD){
        String respuesta="Export ไม่สำเร็จ";
        int numFila=tablaD.getRowCount(), numColumna=tablaD.getColumnCount();
        if(archivo.getName().endsWith("xls")){
            wb = new HSSFWorkbook();
        }else{
            wb = new XSSFWorkbook();
        }
        Sheet hoja = wb.createSheet("Pruebita");
        
        try {
            for (int i = -1; i < numFila; i++) {
                Row fila = hoja.createRow(i+1);
                for (int j = 0; j < numColumna; j++) {
                    Cell celda = fila.createCell(j);
                    if(i==-1){
                        celda.setCellValue(String.valueOf(tablaD.getColumnName(j)));
                    }else{
                        celda.setCellValue(String.valueOf(tablaD.getValueAt(i, j)));
                    }
                    wb.write(new FileOutputStream(archivo));
                }
            }
            respuesta="Export สำเร็จ";
        } catch (Exception e) {
            
        }
        return respuesta;
    }
    
    
    /*public class DateCellRenderer extends DefaultTableCellRenderer {
    public DateCellRenderer() { super(); }

    @Override
    public void setValue(Object value) {
        SimpleDateFormat sdf = new SimpleDateFormat("MM/dd/yy");

        setText((value == null) ? "" : sdf.format(value));
    }
}*/

}