formData请求接口传递参数格式

element ui组件方法的传递//引入 组件。<el-upload    class="avatar-uploader"    :action="action"    :http-request="uploadFile"    :show-file-list="false">    <img v-if="imageUrl" :src="imageUrl" class="avatar">    <i v-else class="el-icon-plus avatar-uploader-icon"></i></el-upload>uploadFile(data){        var userinfo = this.$baseMethod.getStore('_ccmUser')        let formdata = new FormData();        formdata.append('file',data.file);        formdata.append('token',userinfo.token);        formdata.append('op',"uploadChannelPic");        formdata.append('data',JSON.stringify({}));    uploadFile(formdata).then(res => {        this.imageUrl = JSON.parse(res.data).picUrl        // console.log(JSON.parse(res.data))    })},

<input type="file" id="file"  //设置上传格式化accept="image/jpg,image/jpeg,image/png,image/gif"   //获取上传内容@change="fileUpload()" />fileUpload() {  var f = document.getElementById('file').files[0];  let formdata = new FormData()  formdata.append('file',f);  formdata.append('token',storage.get('loginToken'));  formdata.append('op',"uploadChannelPic");       formdata.append('data',JSON.stringify({}));//这里是请求接口进行传递formdata   this.$upload("/channel/perfection/uploadFile",formdata ).then(res => {
　　//请求成功后赋值给要展示的图片    this.fileImg = JSON.parse(res.data).picUrl  })},