How do I write to an Excel file using JRuby and POI?

poi_write_excel_file.rb

# translated from Java example here: http://www.avajava.com/tutorials/lessons/how-do-i-write-to-an-excel-file-using-poi.html
# and upgraded to POI 3.8

require 'java'

def write_test_file
  file_out = java.io.FileOutputStream.new('test1.xlsx')
  workbook = org.apache.poi.xssf.usermodel.XSSFWorkbook.new
  worksheet = workbook.create_sheet("POI Worksheet")

  # index from 0,0... cell A1 is cell(0,0)
  row1 = worksheet.createRow(0)
  cell_a1 = row1.createCell(0)
  cell_a1.cell_value = "Hello"
  cell_style = workbook.create_cell_style

  cell_style.fill_foreground_color = org.apache.poi.hssf.util.HSSFColor::GOLD.index
  cell_style.fill_pattern = org.apache.poi.ss.usermodel.CellStyle::SOLID_FOREGROUND
  cell_a1.cell_style = cell_style


  cell_b1 = row1.createCell(1)
  cell_b1.cell_value = "Goodbye"
  cell_style = workbook.create_cell_style

  cell_style.fill_foreground_color = org.apache.poi.hssf.util.HSSFColor::LIGHT_CORNFLOWER_BLUE.index
  cell_style.fill_pattern = org.apache.poi.ss.usermodel.CellStyle::SOLID_FOREGROUND
  cell_b1.cell_style = cell_style

  cell_c1 = row1.createCell(2)
  cell_c1.cell_value = true

  cell_d1 = row1.createCell(3)
  cell_d1.cell_value = java.util.Date.new

  cell_style = workbook.create_cell_style
  cell_format = workbook.create_data_format
  cell_style.data_format = cell_format.get_format("m/d/yy h:mm")
  cell_d1.cell_style = cell_style

  workbook.write(file_out)
  file_out.flush
  file_out.close
end

write_test_file

PoiWriteExcelFile.java

// source: http://www.avajava.com/tutorials/lessons/how-do-i-write-to-an-excel-file-using-poi.html

package test;

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

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFDataFormat;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.hssf.util.HSSFColor;

public class PoiWriteExcelFile {

	public static void main(String[] args) {
		try {
			FileOutputStream fileOut = new FileOutputStream("poi-test.xls");
			HSSFWorkbook workbook = new HSSFWorkbook();
			HSSFSheet worksheet = workbook.createSheet("POI Worksheet");

			// index from 0,0... cell A1 is cell(0,0)
			HSSFRow row1 = worksheet.createRow((short) 0);

			HSSFCell cellA1 = row1.createCell((short) 0);
			cellA1.setCellValue("Hello");
			HSSFCellStyle cellStyle = workbook.createCellStyle();
			cellStyle.setFillForegroundColor(HSSFColor.GOLD.index);
			cellStyle.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
			cellA1.setCellStyle(cellStyle);

			HSSFCell cellB1 = row1.createCell((short) 1);
			cellB1.setCellValue("Goodbye");
			cellStyle = workbook.createCellStyle();
			cellStyle.setFillForegroundColor(HSSFColor.LIGHT_CORNFLOWER_BLUE.index);
			cellStyle.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
			cellB1.setCellStyle(cellStyle);

			HSSFCell cellC1 = row1.createCell((short) 2);
			cellC1.setCellValue(true);

			HSSFCell cellD1 = row1.createCell((short) 3);
			cellD1.setCellValue(new Date());
			cellStyle = workbook.createCellStyle();
			cellStyle.setDataFormat(HSSFDataFormat
					.getBuiltinFormat("m/d/yy h:mm"));
			cellD1.setCellStyle(cellStyle);

			workbook.write(fileOut);
			fileOut.flush();
			fileOut.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}

	}
}