Apache POI - Java İle Excelde Sistem Tarihini Belirlenen Formatta Hücreye Yazmak

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Date;

import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFCreationHelper;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;

public class HSSFTest {

 
  public static void main(String[] args) {
    
    //Excel Calisma Kitabini Olustur
    HSSFWorkbook workbook = new HSSFWorkbook();
    
    //Excel Sayfasi Olustur
    HSSFSheet sheet = workbook.createSheet("Java4Fun");
    
    HSSFCreationHelper createHelper = workbook.getCreationHelper();
    HSSFCellStyle cellStyle = workbook.createCellStyle();
    cellStyle.setDataFormat(createHelper.createDataFormat().getFormat("m/d/yy h:mm"));
    
    Row row = sheet.createRow(0);
    Cell cell = row.createCell(0);
    cell.setCellValue(new Date());
    cell.setCellStyle(cellStyle);
    
    //Olusturulan Workbook nesnesini dosyaya yaz
    try 
    {
         FileOutputStream out = new FileOutputStream(new File("K:\\test.xls"));
         workbook.write(out);
         out.close();
    } 
    catch (FileNotFoundException e) {
      e.printStackTrace();
    } 
    catch (IOException e) {
         e.printStackTrace();
    }
   
   
  }
  
}