官方文档：https://cn.vuejs.org/v2/cookbook/using-axios-to-consume-apis.html
main.js:

import Vue from 'vue'
import App from './App'
import router from './router'
import axios from 'axios'

Vue.config.productionTip = false
Vue.prototype.axios = axios

new Vue({
  el: '#app',
  router,
  components: { App }, // App就是App.vue组件
  template: '<App/>', // 模版名要跟组件名一样
  mounted(){
    axios.get('https://api.coindesk.com/v1/bpi/currentprice.json').then(function (response) {  //https://api.coindesk.com/v1/bpi/currentprice.json 是接口
      console.log(response)
    }).catch(function () {
      console.log('错误')
    })
  }
})