1.安装：npm install vue-i18n 2.在main.js引入i18n,注册，并设置element语言

import i18n from './lang' 
// set ElementUI lang ,兼容elementui写法
Vue.use(ElementUI, { i18n: (key, value) => i18n.t(key, value) })
new Vue({
  el: '#app',
  router,
  store,
  i18n,
  render: h => h(App)
})

3.src/lang/index.js文件中

import Vue from 'vue'
import VueI18n from 'vue-i18n'
import Cookies from 'js-cookie'
import elementEnLocale from 'element-ui/lib/locale/lang/en' // element-ui lang
import elementZhLocale from 'element-ui/lib/locale/lang/zh-CN'// element-ui lang
import enLocale from './en'
import zhLocale from './zh'

Vue.use(VueI18n)

const messages = {
  en: {
    ...enLocale,
    ...elementEnLocale
  },
  zh: {
    ...zhLocale,
    ...elementZhLocale
  },

}
export function getLanguage() {
  const chooseLanguage = Cookies.get('language')
  // const chooseLanguage = localStorage.get('language')
  if (chooseLanguage) return chooseLanguage

  // if has not choose language
  const language = (navigator.language || navigator.browserLanguage).toLowerCase()
  const locales = Object.keys(messages)
  for (const locale of locales) {
    if (language.indexOf(locale) > -1) {
      return locale
    }
  }
  return 'en'
}
const i18n = new VueI18n({
  // set locale
  // options: en | zh | es
  locale: 'zh',
  // set locale messages
  messages
})

export default i18n

4.准备语言包

5.使用方式 （1）双括号{{$t('xxx.yyy')}}

<p @click="showWarning">{{$t('login.username')}}

(2)绑定到属性上 :prop="$t('xxx.yyy')"

:placeholder="$t('placeholder.date')">

（3）在js中使用${this.$t('xxx.yyy')}//注意使用反引号

`${this.$t('xxx.yyy')}`