使用formData上传文件，ajax上传

<input type="file" name="fileTable"  @change="changeFile($event)" ref="fileTable">

data(){
    return {
      fileTable:'' 
    }
  },
  methods:{//导入文件
    changeFile(e) {
      var file = e.target.files[0]
      var reader = new FileReader()
      var that = this
      reader.readAsDataURL(file)
      reader.onload = function(e) {
        that.fileTable = this.result;
        that.uploadFile();
      }
    },
    uploadFile:function(){
      if (this.$refs.fileTable.files.length !== 0) {
        var file = new FormData()
        file.append('uploadExcel', this.$refs.fileTable.files[0])
        console.log(file);
        $.ajax({
          url:baseUrl + '/usergroup/templateimport',
          type:'post',
          data:file,
          datatype: 'json',
          cache:false,
          traditional: true,
          contentType: false,
          processData: false,
          success: function (res) {
            console.log(res);
          },
          error: function (error) {
            console.log(error);
          }
        });
      }
    }
    
  }