如何从vue父组件中获取子组件中的数据

<FormItem label="上传头像" prop="image">
 <uploadImg :width="150" :height="150" :name="'avatar'" size="150px*150px" ref="avatar"></uploadImg></FormItem>
 <FormItem label="上传营业执照" prop="businessLicence">
 <uploadImg :width="350" :height="200" :name="'businessLicence'" size="350px*200px" ref="businessLicence"></uploadImg></FormItem>

/*
 子组件*/<template>
 <input type='file' @change="changeUrl" />
</template>
<script>export default {
 methods: {
 changeUrl(e) { 
 this.$emit('changeUrl', e.currentTarget.files[0].path)
 }
 }
}</script>/*
 父组件*/<template>
 <FormItem label="上传营业执照" prop="businessLicence">
 <uploadImg :width="350" :height="200" :name="'license'" size="350px*200px" @changeUrl="getUrl"></uploadImg>
 </FormItem>
</template>
<script>export default {
 methods: {
 getUrl(path) { //这个就是你要的path,并且会双向绑定 }
 }
}</script>