Parse Excel with JRuby and POI

excel_controller.rb

require "java"

class ExcelController < ApplicationController

  # Controller method
  def parse_uploaded_file
    excel_file = params[:excel_file]  # file input element
    begin
      parsed_data = parse_excel(excel_file[0].read)
      render :json => {:result => "OK"}
    rescue Exception => e
      logger.error "BOOM : #{e.inspect}"
      render :json => {:result => "Error"}
    end
  end

  private
  def parse_excel content
    upload_is = java.io.ByteArrayInputStream.new(content.to_java_bytes)
    excel_fs = org.apache.poi.poifs.filesystem.POIFSFileSystem.new(upload_is)
    work_book = org.apache.poi.hssf.usermodel.HSSFWorkbook.new(excel_fs)
    sheet = work_book.sheet_at 0
    out_data = []
    sheet.row_iterator.entries.each do |row|
      out_data << row.cell_iterator.entries.map{|c| cell_value(c)}
    end
    out_data
  end

  def cell_value cell
    case cell.cell_type
      when org.apache.poi.ss.usermodel.Cell::CELL_TYPE_NUMERIC then cell.numeric_cell_value
      when org.apache.poi.ss.usermodel.Cell::CELL_TYPE_STRING  then cell.string_cell_value
      when org.apache.poi.ss.usermodel.Cell::CELL_TYPE_FORMULA then cell.numeric_cell_value
      else "**ERROR** #{cell.cell_type}"
    end
  end

end

may not work as it is because I took out some business logic which was not relevant to the parsing part