Layout

D:\workspace\xxx\src\main.js

import Vue from 'vue'
import Layout from './components/layout'

/* eslint-disable no-new */
new Vue({
  el: '#app',
  template: '<Layout/>',
  components: { Layout }
})

　　

D:\workspace\xxx\src\components\layout.vue

<template>
    <div>
      <div class="app-header">header</div>
      <div class="app-content">content</div>
      <div class="app-footer">footer</div>
    </div>
</template>

<script>
export default {
  name: 'Layout',
  data () {
  }
}
</script>