无法加载Ruby gem -加载错误-在mysql2文件中

Question

当我在一个简单的ruby文件中运行以下代码时：

require 'mysql2'
client = Mysql2::Client.new(:host => "localhost", :username => "root")

我得到了以下响应。

/usr/local/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- mysql2/mysql2 (LoadError)
    from /usr/local/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /usr/local/lib/ruby/gems/2.3.0/gems/mysql2-0.4.8/lib/mysql2.rb:31:in `<top (required)>'
    from /usr/local/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:133:in `require'
    from /usr/local/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:133:in `rescue in require'
    from /usr/local/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:40:in `require'

我没有在RoR中使用这个gem，现在只是纯粹的ruby修补。我通过Homebrew安装了这个gem。

版本。

gem list mysql2 --> mysql2 (0.4.8)

mysql版本14.14发行版5.7.19，用于osx10.11 (x86_64)

ruby 2.3.1p112 (54768-04-26修订版) x86_64-darwin15

Answer 1

在ruby文件所在的目录中创建Gemfile

# Gemfile

source "https://rubygems.org"

gem "mysql2"

然后做bundle install

然后做bundle exec ruby my_simple_ruby_file.rb