Vue.use(VueI18n); // 通过插件的形式挂载

const i18n = new VueI18n({
    locale: 'zh-CN',    // 语言标识
    //this.$i18n.locale // 通过切换locale的值来实现语言切换
    messages: {
        'zh-CN': require('./utils/lang/zh'),   // 中文语言包
        'en-US': require('./utils/lang/en')    // 英文语言包
    }
});

....

new Vue({
    router,
    i18n, //看这里
    render: h => h(App),
}).$mount('#app');

export const m = {
    webSiteTitle: '阳光沙滩用户管理中心',
    userInfo: '用户信息',
    logout: '退出登录',
    index: '首页',
};

export const m = {
    webSiteTitle: 'ICAdminCenter',
    userInfo: 'User Info',
    logout: 'Logout',
    index: 'index',
};

<div class="header-left-box float-left">
	<div class="header-logo">{{$t('m.webSiteTitle')}}</div>
</div>

<el-menu-item :index="item.path">
	<i :class="item.icon"></i>
	<span slot="title">{{$t(item.name)}}</span>
</el-menu-item>

<el-dropdown @command="handlerLan">
	  <span class="lan-selector">
		<i class="el-icon-set-up"></i>{{currentLan}}
	  </span>
	<el-dropdown-menu slot="dropdown">
		<el-dropdown-item :command="item" v-for="(item,index) in lanList" :key="index">
			{{item.name}}
		</el-dropdown-item>
	</el-dropdown-menu>
</el-dropdown>

lanList: [{
	name: '简体中文',
	value: 'zh-CN'
}, {
	name: 'English',
	value: 'en-US'
}]

handlerLan(item) {
	//设置语言
	this.$i18n.locale = item.value;
	//保存到本地
	window.localStorage.setItem('lan-value', item.value);
	window.localStorage.setItem('lan-name', item.name);
	this.currentLan = item.name;
}