Upload File Api请求在邮递员中有效，但在nodejs中不起作用，并且对MERN有反应

我正在制作文件上传和媒体API，在Postman中可以正常工作，但在代码中不行

反应代码：

campaignChangedHandler = (event) => {
   this.setState(
        {
            campaignFile: document.getElementById('campaignFile').files[0]
        })
};

onSubmit = async(e) => {
   let formData = new FormData();
    formData.append('campaignFile', this.state.campaignFile);

     const headers = {
        'Authorization': `Bearer ${token}`
     };

      await axios.post('http://localhost:3001/upload/', {formData}, {headers}).then(resp => {
         console.log(resp)
      })
};


render() {
  return (
    <form onSubmit={this.onSubmit}>
        <input value={this.state.data} error={errors.data}
            onChange={this.campaignChangedHandler}
            name={"campaignFile"}
            id="campaignFile"
            type="file"/>
    </form>
  )
}

NODE JS代码：

const fileUpload = require('express-fileupload');
app.use(fileUpload());

app.post('/upload', function (req, res) {
   console.log(req.files);
}

[我总是在Nodejs控制台中得到不确定的信息，我尝试过使用多方，multer和busboy，但是得到了相同的结果，但是在邮递员中，我得到了这个：

response from postman

尝试一下：

constructor(props) {
    super(props);
      this.state = {
        campaignFile: null
      }

  }



 onChangeHandler=event=>{
    this.setState({
      campaignFile: event.target.files[0],
    })
  }



 onSubmit = async(e) => {
   let formData = new FormData();
   formData.append('campaignFile', this.state.selectedFile);

     const headers = {
        'Content-Type': 'multipart/form-data',
        'Authorization': `Bearer ${token}`
     };

      await axios.post('http://localhost:3001/upload/',formData,headers).then(resp => {
         console.log(resp)
      })
};


render() {
  return (
    <form onSubmit={this.onSubmit}>
        <input type="file" name="campaignFile" onChange={this.onChangeHandler}/>
    </form>
  )
}