配置两个文件

config/index.js

build: {
    assetsPublicPath: './',
  }

build/utils.js

function generateLoaders (loader, loaderOptions) {
    const loaders = options.usePostCSS ? [cssLoader, postcssLoader] : [cssLoader]
 
    if (loader) {
      loaders.push({
        loader: loader + '-loader',
        options: Object.assign({}, loaderOptions, {
          sourceMap: options.sourceMap
        })
      })
    }
 
    // Extract CSS when that option is specified
    // (which is the case during production build)
    if (options.extract) {
      return ExtractTextPlugin.extract({
        use: loaders,
        fallback: 'vue-style-loader',
        publicPath:'../../',
      })
    } else {
      return ['vue-style-loader'].concat(loaders)
    }
  }