是fis3的热更新监听8080吗？

vue-cli里基本包括了这些功能，我认为没必要再用fis3，不知道你用fis3的目的是什么？

如果非要用，你可以在config里找到项目的端口改一下。

config/index.js

// see http://vuejs-templates.github.io/webpack for documentation.

var path = require('path')

module.exports = {

  build: {

    env: require('./prod.env'),

    index: path.resolve(__dirname, '../dist/index.html'),

    assetsRoot: path.resolve(__dirname, '../dist'),

    assetsSubDirectory: 'static',

    assetsPublicPath: '/',

    productionSourceMap: true,

    // Gzip off by default as many popular static hosts such as

    // Surge or Netlify already gzip all static assets for you.

    // Before setting to `true`, make sure to:

    // npm install --save-dev compression-webpack-plugin

    productionGzip: false,

    productionGzipExtensions: ['js', 'css']

  },

  dev: {

    env: require('./dev.env'),

    port: 8080,

    assetsSubDirectory: 'static',

    assetsPublicPath: '/',

    proxyTable: {},

    // CSS Sourcemaps off by default because relative paths are "buggy"

    // with this option, according to the CSS-Loader README

    // (https://github.com/webpack/css-loader#sourcemaps)

    // In our experience, they generally work as expected,

    // just be aware of this issue when enabling this option.

    cssSourceMap: false

  }

}

在config文件里修改端口 

我用的是fis3前端构建工具，fis3他会默认的占用8080端口，如果端口被占用的了话，npm run dev 也会报错的