ERROR:  Error installing json:The ‘json‘ native gem requires installed build tools.

C:\ruby\blog>gem install json -v ‘1.8.3‘
ERROR:  Error installing json:The ‘json‘ native gem requires installed build tools.

Please update your PATH to include build tools or download the DevKit
from ‘http://rubyinstaller.org/downloads‘ and follow the instructions
at ‘http://github.com/oneclick/rubyinstaller/wiki/Development-Kit‘

在 windows下搭建Ruby Rails Web开发环境 时遇到这个问题，

 发生这个错误的原因是没有安装DevKit

DevKit

加上devkit之后，你的ruby中便具有了一个mingw32的本地编译环境，而且这个本地编译环境是自动调用的。只有在你要安装的gem需要本地编译时，才会调用devkit。 

http://rubyinstaller.org/add-ons/devkit

下载DevKit

http://rubyinstaller.org/downloads

安装DevKit

1、运行，解压到一个目录，例如：C:\DevKit

2、打开命令行，切换到这个目录；

3、执行命令：ruby dk.rb init

4、修改config.yml文件

5、执行命令：ruby dk.rb install

安装完DevKit之后，再执行命令安装JSON包：gem install json -v ‘1.8.3‘

安装过程中可能会出现以下问题：

C:\ruby\blog>gem install json -v ‘1.8.3‘
ERROR:  While executing gem ... (Gem::RemoteFetcher::FetchError)
    Errno::ECONNABORTED: An established connection was aborted by the software i
n your host machine. - SSL_connect (https://api.rubygems.org/quick/Marshal.4.8/json-1.8.3.gemspec.rz)

https://github.com/oneclick/rubyinstaller/wiki/Development-Kit

ERROR: Error installing json:The 'json' native gem requires installed build tools.

原文：http://blog.csdn.net/testcs_dn/article/details/50275683