＆＃34;要求＆＃34;：无法加载此类文件 - open-url（LoadError）

Question

这是我的.rb代码。请帮忙，非常感谢你！

require 'open-uri'
require 'nokogiri'

url = "http://en.wikipedia.org/wiki/List_of_current_NBA_team_rosters"
page = Nokogiri::HTML(open(uri))

puts page

这是我的命令提示符中出现的错误：

  

C：\ Sites＆gt; ruby​​ wikipedia_scraper.rb   C：/RailsInstaller/Ruby2.3.​​0/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in require': cannot load such file -- open-url (LoadError from C:/RailsInstaller/Ruby2.3.0/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in要求＆＃39;           来自wikipedia_scraper.rb：1：在`＆＃39;