webpack打开网页显示cannot get /

**在配置webpack-dev-server时打开网页显示cannot get /，
并且控制台输出
[webpack-dev-server] Content not from webpack is served from 'D:\html5\webpack学习\change-rows-colors' directory

查阅webpack官方文档后发现，需要在webpack.config.js的devServer中添加以下代码以显示当前项目的目录结构