elementui使用el-upload组件如何实现自定义上传

<el-upload
   class="pad"
   ref="upload"
   action="action"
   :http-request="uploadBpmn"
   :before-upload="beforeUpload">
   <el-button size="medium" type="primary" class="el-icon-upload"> 部署流程定义</el-button>
 </el-upload>

beforeUpload (file) { // 上传文件之前钩子
  const type = file.name.split('.')[1]
  if (type !== 'bpmn') {
    this.$message({ type: 'error', message: '只支持bpmn文件格式！' })
    return false
  }
},
uploadBpmn (param) { // 部署流程定义（点击按钮，上传bpmn文件，上传成功后部署，然后重新加载列表）
  const formData = new FormData()
  formData.append('processDefinition', param.file) // 传入bpmn文件
  this.$API({
    name: 'deploy',
    data: formData,
    headers: {'Content-Type': 'multipart/form-data'}
  }).then(res => {
    if (res.data.code == 0) {
      this.$message({ type: 'success', message: res.data.msg })
    } else {
      this.$message({ type: 'error', message: res.data.msg })
    }
  }).catch(error => {
    this.$message({ type: 'error', message: error })
  }).finally(() => {
    this.getList()
  })
},

::v-deep .el-upload-list {
  display: none !important;
}

<template>
  <div class="app-upload">
    <div class="upload-title">上传文件</div>
    <el-upload
      class="upload-demo"
      ref="uploadBox"
      drag
      action="action"
      :before-upload="beforeUpload"
      :http-request="upload"
      :auto-upload="false"
      multiple>
      <i class="el-icon-upload"></i>
      <div class="el-upload__text">将文件拖到此处，或<em>点击上传</em></div>
    </el-upload>
    <div class="upload-btn">
      <el-button type="primary" @click="sure" :loading="loading">确 定</el-button>
    </div>
  </div>
</template>

<script>
const formData = new FormData()
export default {
  data () {
    return {
      loading: false
    }
  },
  methods: {
    beforeUpload (file) { // 上传文件之前钩子
      formData.append('files', file)
    },
    upload () {
      this.loading = true
      this.$API({
        name: 'UploadResource',
        data: formData,
        params: {
          path: this.$route.query.path
        },
        requireAuth: true
      }).then (res => {
        if (res.data.code === 200) {
          this.$notify.success(res.data.msg)
        } else {
          this.$notify.error(res.data.msg)
        }
      }).catch(error => {
        this.$notify.error(error)
      }).finally(() => {
        this.loading = false
        this.reset()
      })
    },
    sure () {
      this.$refs.uploadBox.submit()
    },
  }
}
</script>

  mounted() {
    if (this.$route.query.type === 'folder') {
      this.$nextTick(() => {
        document.querySelector('.el-upload__input').webkitdirectory = true
      })
    }
  },

// 自定义的全局组件my-component
let _utils = new Utils()
Vue.component(
    'uploadfile', {
        props: {
            uploaddata: {
                type: Object
            }
        },
        template: `<div style="margin:20px 0;">
<el-upload
  accept=".xls,.xlsx"
  class="upload-demo"
  :action="uploaddata.url"
  :before-upload="beforeUpload"
  :on-success="handleSuccess"
  :on-preview="handlePreview"
  :on-remove="handleRemove"
  :before-remove="beforeRemove"
  :limit="2"
  :on-exceed="handleExceed">
  <span>表名称:{{uploaddata.sheetname}}</span>
  <el-button size="small" type="primary">选择文件</el-button>
<!--  <div slot="tip" class="el-upload__tip">只能上传jpg/png文件，且不超过500kb</div>-->
</el-upload>
</div>`,
        data() {
            return {}
        },
        methods: {
            /*
            上传文件之前的钩子，参数为上传的文件，
            若返回 false 或者返回 Promise 且被 reject，则停止上传。
             */
            beforeUpload(file){
                const fileSuffix = file.name.substring(file.name.lastIndexOf(".")+1);
                const whiteList = ["xls", "xlsx"];
                if (whiteList.indexOf(fileSuffix) === -1) {
                    _utils.MessageError(this,"上传文件只能是xls、xlsx格式")
                    return false;
                }
                const isLt2M = file.size / 1024 / 1024 < 5;
                if (!isLt2M) {
                    _utils.MessageError(this,"上传文件大小不能超过5MB")
                    return false;
                }
            },
            handleRemove(file, fileList) {
             
            },
            handleSuccess(response, file, fileList) {
                let {code, msg} = response
                if (code == 0) {
                    utils.MessageSuccess(this, "文件上传成功")
                } else {
                    utils.MessageError(this, msg)
                }
            },
            /*
            点击文件列表中已上传的文件时的钩子
             */
            handlePreview(file) {
                // console.log(file);
            },
            /*
             文件超出个数限制时的钩子
             */
            handleExceed(files, fileList) {
            },
            /*
            删除文件之前的钩子，参数为上传的文件和文件列表，
            若返回 false 或者返回 Promise 且被 reject，则停止删除
             */
            beforeRemove(file, fileList) {
                // return this.$confirm(`确定移除 ${file.name}？`);
            }
        }
    }
)