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

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

# This configuration file contains the absolute path locations of all
# installed Rubies to be enhanced to work with the DevKit. This config
# file is generated by the 'ruby dk.rb init' step and may be modified
# before running the 'ruby dk.rb install' step. To include any installed
# Rubies that were not automagically discovered, simply add a line below
# the triple hyphens with the absolute path to the Ruby root directory.
#
# Example:
#
# ---
- C:\Ruby22-x64
# - C:/ruby192dev
#
---

C:\Ruby22-x64 是我的Ruby安装目录

5、执行命令：ruby dk.rb install

C:\DevKit>ruby dk.rb install
[INFO] Updating conve

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)

这可能是由于网络的原因，多试几次就好了。

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