# 壹、安装

1.下载node.js，使用npm安装
“`xml
npm install -g yarn
查看版本：yarn –version
“`

2.安装node.js,下载yarn的安装程序:

[ 提供一个.msi文件，在运行时将引导您在Windows上安装Yarn](https://yarnpkg.com/en/docs/install#windows-stable)

3.Yarn 淘宝源安装，分别复制粘贴以下代码行到黑窗口运行即可
“`xml
yarn config set registry https://registry.npm.taobao.org -g
yarn config set sass_binary_site http://cdn.npm.taobao.org/dist/node-sass -g

“`
# 贰、踩坑时刻
1.yarn使用时候报错信息：
“`xml
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.
“`
2.检测yarn版本 yarn version
“`xml
D:\Seven\ways\hadoop-2.7.3>yarn version ok
Hadoop 2.7.3
Subversion https://git-wip-us.apache.org/repos/asf/hadoop.git -r b3fe56402d908019d99af1f1f4fc65cb1d1436a2
Compiled by jdu on 2017-12-05T03:43Z
Compiled with protoc 2.5.0
From source with checksum 9ff4856d824e983fa510d3f843e3f19d
This command was run using /D:/Seven/ways/hadoop-2.7.3/share/hadoop/common/hadoop-common-2.7.3.jar
“`
3.检测yarn版本 yarn –version 报错
“`xml
D:\Seven\ways\hadoop-2.7.3>yarn –version
Unrecognized option: –version
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.
“`
4.安装依赖包 报错
“`xml
D:\Seven\ways\hadoop-2.7.3>yarn install
错误: 找不到或无法加载主类 install
“`
5.最后没办法重新下载windows安装包[ 提供一个.msi文件，在运行时将引导您在Windows上安装Yarn](https://yarnpkg.com/en/docs/install#windows-stable)

安装 -> 测试 -> 报错 -> 检测原因 -> 没有配置环境变量 -> 继续报错,检测原因 -> java安装环境中有默认的yarn -> 环境变量配置在它前面

6.测试
“`xml
Microsoft Windows [版本 10.0.18362.239]
(c) 2019 Microsoft Corporation。保留所有权利。

C:\Users\Chirius>yarn –version
1.17.3

C:\Users\Chirius>
“`