https://ruby-china.org/supersheep en-us <p>尝试直接 hash.to_json 报 undefined method `to_json' for {"a"=&gt;1}:Hash (NoMethodError) 于是 sudo gem install json Fetching: json-1.7.5.gem (100%) Building native extensions. This could take a while... Successfully installed json-1.7.5 1 gem installed Installing ri documentation for json-1.7.5... Installing RDoc documentation for json-1.7.5...</p> <p>require 'json' 报 main.rb:3:in `require': no such file to load -- json (LoadError)</p> <p>然后我就没辙了，求解。</p> supersheep Sat, 01 Dec 2012 20:42:59 +0800 https://ruby-china.org/topics/7248 https://ruby-china.org/topics/7248