CSV 导入导出详解编程语言

csv_string = FasterCSV.generate do |csv| csv ["name","detail","price","num","category_id"] Product.find(:all).each do |p| csv [p.name, p.detail, p.price, p.num, p.category_id] end end csv_string = NKF.nkf("-s",csv_string) send_data csv_string, :type= text/csv;,:disposition = "attachment; filename=product.csv" end def self.import_db(file, model_str) field_names = eval(model_str).column_names field_names.delete("id") field_names.delete("deleted_at") params_value = {} file_path = "#{RAILS_ROOT}/tmp/csv/" Dir.mkdir(file_path,0777) unless File.exist?(file_path) file_name = "temp.csv" data_utf = file.read File.open(file_path + file_name , wb+) do |f| f.write(data_utf) end key_id = Time.now.strftime(%Y%m%d%H%M%S) system(" nkf -w #{file_path + file_name} #{file_path + key_id + file_name}") messages = [] f_path = file_path + key_id + file_name index = -1 eval(model_str).transaction do FasterCSV.foreach(f_path) do |row| index += 1 next if index == 0 #开始垃圾处理，对象垃圾回收站，GC.start GC.start if index % 50 == 0 row.each do |r| r = r.to_s.toutf8 unless r.blank? end field_names.each_with_index { |name, name_index| params_value["#{name}"] = row[name_index]} model = eval(model_str).new(params_value) if model.valid? model.save! else messages "第#{index}行#{model.errors.full_messages}" end end end FileUtils.rm_rf(file_path) if File.exists?(file_path) return messages end

 

def export 

 send_data Export.export_csv("Product"), :type= text/csv, 

 :disposition = "attachment", 

 :filename = "product_#{Time.now.strftime(%Y%m%d%H%M%S)}.csv" 

 end 

def self.export_csv(model) 

 #动态取得model 

 field_names = eval(model).column_names 

 field_names.delete("id") 

 field_names.delete("deleted_at") 

 csv_string = FasterCSV.generate do |csv| 

 #得到所有的modle字段 

 csv field_names 

 eval(model).find(:all).each do |m| 

 csv field_names.collect {|name| m.send(name)} 

 end 

 end 

 csv_string = NKF.nkf("-w", csv_string) 

 end

 

 

使用 %= file_field_tag file % ，在form表单中加入action指向csv_import，记得加上:enctype = multipart/form-data 哦，不然不能上传文件。

 % form_for :attachment, :url = { :controller = "attachment", :action = "import_to_db" }, 

 :html = { :multipart = true } do |f| % 

 csv导入： %= f.file_field :csv % 

 br / 

 %= submit_tag "导入csv" % 

 % end % 

 

def self.import_to_db(file) 

 file_path = "#{RAILS_ROOT}/tmp/csv/" #创建文件夹 

 FileUtils.mkdir(file_path) if !File.exist?(file_path) 

 #临时文件命名，不能有非法字符，比如"()"因为在linux下文件名不支持"()"等特殊符号 

 file_name = "temp.csv" 

 begin 

 data_utf = file.read#Iconv.conv("UTF-8//IGNORE","shift_jis//IGNORE",params[:csv_file].read) 

 File.open(file_path + file_name , wb) do |f| 

 f.write(data_utf) 

 f.close 

 end 

 ensure 

 file.close 

 end 

 key_id = UUID.random_create().to_s 

 system("nkf -Lu -S -w80 #{file_path + file_name} #{file_path + key_id + file_name}") 

 messages = [] 

 f_path = file_path + key_id + file_name 

 index = -1 

 Attachment.transaction do 

 FasterCSV.foreach(f_path) do |row| 

 flag = true 

 index += 1 

 next if index == 0 

 GC.start if index % 50 == 0 

 row.each do |r| 

 r = r.to_s.toutf8 unless r.blank? 

 end 

 attachment = Attachment.new 

 attachment.id = row[0] 

 attachment.type = row[1] 

 attachment.owner_id = row[2] 

 attachment.url = row[3] 

 attachment.name = row[4] 

 attachment.created_at = row[5] 

 attachment.updated_at = row[6] 

 attachment.deleted_at = row[7] 

 if attachment.save 

 messages "第#{index}行#{attachment.errors.full_messages}" 

 end 

 end 

 end 

 FileUtils.rm_rf(file_path) if File.exists?(file_path) 

 return messages 

 end

 

原创文章，作者：ItWorker，如若转载，请注明出处：https://blog.ytso.com/13410.html

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