上传后改变图片的名字，进行自定义，避免传重复的图片

        <el-upload
          class="upload-demo"
          :action="uploadUrl"
          :file-list="ruleForm.fileList"
          :before-upload="beforeUploadFile"
          :on-error="handleError"
          :on-exceed="handleExceed"
          :limit="1"
          :on-progress="upLoading"
        >
          <el-button
            v-loading.fullscreen.lock="fullscreenLoading"
            size="small"
            type="primary"
          >
            点击上传
          </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>

里面的action，不能为空，官方为必填，否则会报错,随便写个，只要不为空就行

    uploadUrl() {
      let downLoadUrl = location.href.indexOf('education') > -1 ? '' : '/api'
      return downLoadUrl + '/api-system/sys/file/uploadFile'
    }

相关的验证方法

upLoading() {
      console.log('正在上传')
      this.fullscreenLoading = true
    },
    resetForm(formName) {
      this.$router.history.go(-1)
      this.$refs[formName].resetFields()
    },
    handleChange(file, fileList) {
      /* this.fileList = fileList.slice(-3) */
    },
    // 文件上传成功时的钩子
    handleSuccess(res, file, fileList) {
      console.log(file, '上传成功', fileList)
      this.fullscreenLoading = false
      this.ruleForm.fileList = [
        { name: file.response.datas.name, url: file.response.datas.path }
      ]
      this.$message.success('文件上传成功')
    },
    // 文件上传失败时的钩子
    handleError(err, file, fileList) {
      this.$message.error('文件上传失败')
      this.fullscreenLoading = false
      return false
    },
    beforeUploadFile(file) {
      /* debugger */
      let extension = file.name.substring(file.name.lastIndexOf('.') + 1)
      let size = file.size / 1024 / 1024
      /* console.log(extension, 'extension') */
      if (extension !== 'jpg' && extension !== 'png') {
        this.$message.warning('只能上传后缀是jpg/png的文件')
        return false
      } else if (size > 10) {
        this.$message.warning('文件大小不得超过10M')
        return false
      } else {
      }

      const timeStamp = new Date() - 0
      let nums = this.randomString(5)
      const copyFile = new File(
        [file],
        `${timeStamp}_${nums}.${file.name.split('.')[1]}`
      )
      this.uploadFile(copyFile)
      return false
    },
    uploadFile(file) {
      //const formdata = new FormData()
      //这里后台需要的就是file文件，不是formdata，所以我们不用生成formdata,看各自的需求吧
      //formdata.append('file', file)
      this.postForm(file)
    },
    postForm(file) {
      //uploadPic为后台接口方法
      uploadPic({ file })
        .then(res => {
          if (res.resp_code == 0) {
            // do something
            this.fullscreenLoading = false
            //上传成功后回显的数据
            this.ruleForm.fileList = [
              { name: res.datas.name, url: res.datas.path }
            ]
            this.$message.success('文件上传成功')
          } else {
            this.$message.error(res.msg || res.message || '文件上传失败')
          }
        })
        .catch(err => {
          this.$message.error(err.message || '文件上传失败')
        })
    },
    handleExceed(files, fileList) {
      this.fullscreenLoading = false
      this.$message.warning(
        `当前限制选择 1 个文件，本次选择了 ${
          files.length
        } 个文件，共选择了 ${files.length + fileList.length} 个文件`
      )
    },
    //名字随机数生成方法
    randomString(e) {
      e = e || 32
      var t = 'ABCDEFGHJKMNPQRSTWXYZabcdefhijkmnprstwxyz2345678',
        a = t.length,
        n = ''
      for (let i = 0; i < e; i++) n += t.charAt(Math.floor(Math.random() * a))
      return n
    }