axios作用：Axios 是一个基于 promise 的 HTTP 库，可以用在浏览器和 node.js 中
1.安装

npm install axios

2.入口文件main.js中引入

import axios from 'axios'
Vue.prototype.$axios = axios  // 挂载在vue实例化对象上

3.在config/index.js中的设置proxyTable的值为：

image.png

如果本身的接口地址就有 '/api' 这种通用前缀，就可以把 pathRewrite 删掉
因为在 ajax 的 url 中加了前缀 '/api'，而原本的接口是没有这个前缀的,所以需要通过 pathRewrite 来重写地址，将前缀 '/api' 转为 '/'
4.简约版

this.$axios({
      url: xxxxxxx,
      method: 'post',
      data: JSON.stringify(this.id)
}).then()

5.加强版封装axios

import axios from 'axios'
import { MessageBox, Message } from 'element-ui'
import store from '@/store'
import { getToken } from '@/utils/auth'  // vuex中存好的token

// create an axios instance
const service = axios.create({
  baseURL: process.env, // 根据项目设置 url = base url + request url 
  withCredentials: false, // send cookies when cross-domain requests
  timeout: 5000 // request timeout
})

// request interceptor
service.interceptors.request.use(
  config => {
    // do something before request is sent
    if (store.getters.token) {
      config.headers['X-Token'] = getToken()
    }
    return config
  },

  error => {
    // do something with request error
    console.log(error, "error") // for debug
    // return Promise.reject(error)
  }
)

// response interceptor
service.interceptors.response.use(
  response => {
    const res = response.data
    // if the custom code is not 20000, it is judged as an error.
    if (res.code !== 0) {
      Message({
        message: res.msg,
        type: 'error',
        duration: 5 * 1000
      })

    } else {
      return res
    }
  },
  error => {
    if (error.message == "Request failed with status code 401") {
      Message({
        type: 'error',
        message: '登陆失效,请从新登陆'
      })
      store.dispatch('user/resetToken')
    } else if (error.message == "Request failed with status code 500") {
      Message({
        type: 'error',
        message: '网络连接出错，请稍后再试！'
      })
    } else {
      Message({
        message: error.message,
        type: 'error',
        duration: 5 * 1000
      })
      return Promise.reject(error)
    }
  }
)

export default service

应用：

image.png