老师我试了,还是取不出formData,只能娶到filePath,就是官方实例中 user: ‘test’,怎么在后台取出来

wx.chooseImage({
  success(res) {
    const tempFilePaths = res.tempFilePaths
    wx.uploadFile({
      url: 'https://example.weixin.qq.com/upload', // 仅为示例，非真实的接口地址
      filePath: tempFilePaths[0],
      name: 'file',
      formData: {
        user: 'test'
      },
      success(res) {
        const data = res.data
        // do something
      }
    })
  }
})