vue点击按钮下载：
<span class='down' @click='handelDown'>
<i class='img'></i>
</span>
handelDown() {
window.open(this.$api._api + `/system/dowmloadDict`)
}
a标签下载
<span class='down' >
<a :href='downloadUrl'>
</a>
<i class='img'></i>
</span>
data() {
return {
downloadUrl: this.$api.api + '/system/dowmloadDict'
}
}
