需要用到這個(gè)插件extract-text-webpack-plugin

var ExtractTextPlugin = require('extract-text-webpack-plugin');

 {
                test: /.less$/,
                use: ExtractTextPlugin.extract({
                    fallback: "style-loader",
                    use:[
                        {
                            loader: "css-loader",
                            options: {
                                minimize: true
                            }
                        }, {
                            loader: "less-loader"
                        }]
                }),
            },

    plugins: [
        new ExtractTextPlugin("css/style_[hash].css")
        ]