1、问题代码 views :
<%= file_field_tag "attachment", :accept => 'application/msexcel'%> controller: att_file = params[:attachment].read att_file_name = params[:attachment].original_filename File.open("public/attachment_file", "wb") do |f| f.write(xx) end 2、问题 Permission denied - public/attachment_file

第一次做这种关于文件上传，不太知道这类错误的原因，还请大家帮忙~！！！