npm install vue-i18n

import VueI18n from 'vue-i18n'Vue.use(VueI18n)

const messages = {zh: {message: {hello: '好好学习，天天向上！'}},en: {message: {hello: 'good good study, day day up!'}}
}

const i18n = new VueI18n({locale: 'en', // 语言标识
    messages
})

const app = new Vue({router,i18n,...App
}).$mount('#app')

<div id="app"><h1 style="font-size: 16px; text-align: center;">{{ $t("message.hello") }}</h1></div>

const i18n = new VueI18n({locale: 'zh', // 语言标识
    messages
})

const i18n = new VueI18n({locale: 'en',  // 语言标识
    messages: {'zh': require('./common/lang/zh'),'en': require('./common/lang/en')}
})

// 注意：一定是 exports，不是 export，否则会报错，报错信息是下列的中的内容不是 string
module.exports = {message: {title: '运动品牌'},placeholder: {enter: '请输入您喜欢的品牌'},brands: {nike: '耐克',adi: '阿迪达斯',nb: '新百伦',ln: '李宁'}
}

module.exports = {message: {title: 'Sport Brands'},placeholder: {enter: 'Please type in your favorite brand'},brands: {nike: 'Nike',adi: 'Adidas',nb: 'New Banlance',ln: 'LI Ning'}
}

// HTML
<div id="app"><div style="margin: 20px;"><h1>{{$t("message.title")}}</h1><input style="width: 300px;" class="form-control" :placeholder="$t('placeholder.enter')"><ul><li v-for="brand in brands">{{brand}}</li></ul></div>
</div>// JS
data () {return {brands: [this.$t('brands.nike'), this.$t('brands.adi'), this.$t('brands.nb'), this.$t('brands.ln')]}},

function getCookie(name,defaultValue) {var arr, reg = new RegExp("(^| )" + name + "=([^;]*)(;|$)");if (arr = document.cookie.match(reg))return unescape(arr[2]);elsereturn defaultValue;
}export {getCookie
}

const i18n = new VueI18n({locale: getCookie('PLAY_LANG','zh'),    // 语言标识
    messages: {'zh': require('./common/lang/zh'),'en': require('./common/lang/en')}
})

// template
<h2>{{$t('test')}}</h2>
<button type="button" class="btn btn-success" @click="changeLocale">中文/EN</button>        

// js方法
changeLocale () {this.$confirm(this.$t('layer.toggle'), this.$t('layer.tips'), {confirmButtonText: this.$t('button.ok'),cancelButtonText: this.$t('button.cancel'),type: 'warning'}).then(() => {let locale = this.$i18n.localelocale === 'zh' ? this.$i18n.locale = 'en' : this.$i18n.locale = 'zh'}).catch(() => {this.$message({type: 'info',})      })
},