如何使用 Axios 从表单中发布文件

将文件添加到 formData 对象，并将 Content-Type 标头设置为 multipart/form-data。

var formData = new FormData();
var imagefile = document.querySelector('#file');
formData.append("image", imagefile.files[0]);
axios.post('upload_file', formData, {
    headers: {
      'Content-Type': 'multipart/form-data'
    }
})

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使用 Vue 的示例应用程序。需要在 localhost 上运行的后端服务器来处理请求：

var app = new Vue({
  el: "#app",
  data: {
    file: ''
  },
  methods: {
    submitFile() {
      let formData = new FormData();
      formData.append('file', this.file);
      console.log('>> formData >> ', formData);

      // You should have a server side REST API 
      axios.post('http://localhost:8080/restapi/fileupload',
          formData, {
            headers: {
              'Content-Type': 'multipart/form-data'
            }
          }
        ).then(function () {
          console.log('SUCCESS!!');
        })
        .catch(function () {
          console.log('FAILURE!!');
        });
    },
    handleFileUpload() {
      this.file = this.$refs.file.files[0];
      console.log('>>>> 1st element in files array >>>> ', this.file);
    }
  }
});

https://codepen.io/pmarimuthu/pen/MqqaOE

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如果您不想使用 FormData 对象（例如，您的 API 采用特定的内容类型签名，而 multipart/formdata 不是其中之一），那么您可以这样做：

uploadFile: function (event) {
    const file = event.target.files[0]
    axios.post('upload_file', file, {
        headers: {
          'Content-Type': file.type
        }
    })
}

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这对我有用，我希望对某人有所帮助。

var frm = $('#frm');
let formData = new FormData(frm[0]);
axios.post('your-url', formData)
    .then(res => {
        console.log({res});
    }).catch(err => {
        console.error({err});
    });

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分享我使用 React 和 HTML 输入的经验

定义输入字段

<input type="file" onChange={onChange} accept ="image/*"/>

定义 onChange 监听器

const onChange = (e) => {
  let url = "https://<server-url>/api/upload";
  let file = e.target.files[0];
  uploadFile(url, file);
};

const uploadFile = (url, file) => {
  let formData = new FormData();
  formData.append("file", file);
  axios.post(url, formData, {
      headers: {
        "Content-Type": "multipart/form-data",
      },
    }).then((response) => {
      fnSuccess(response);
    }).catch((error) => {
      fnFail(error);
    });
};
const fnSuccess = (response) => {
  //Add success handling
};

const fnFail = (error) => {
  //Add failed handling
};

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如何使用内存中的对象（如 JSON 对象）发布文件：

import axios from 'axios';
import * as FormData  from 'form-data'

async function sendData(jsonData){
    // const payload = JSON.stringify({ hello: 'world'});
    const payload = JSON.stringify(jsonData);
    const bufferObject = Buffer.from(payload, 'utf-8');
    const file = new FormData();

    file.append('upload_file', bufferObject, "b.json");

    const response = await axios.post(
        lovelyURL,
        file,
        headers: file.getHeaders()
    ).toPromise();


    console.log(response?.data);
}

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对我来说，错误是控制器中的实际参数名称......我花了一段时间才弄清楚，也许它会对某人有所帮助。我正在使用 Next.js / .Net 6

客户：

export const test = async (event: any) => {
    const token = useAuthStore.getState().token;
    console.log(event + 'the event')
    if (token) {
        const formData = new FormData();
        formData.append("img", event);
        const res = await axios.post(baseUrl + '/products/uploadproductimage', formData, {
            headers: {
                'Authorization': `bearer ${token}`
            }
        })
        return res
    }
    return null
}

服务器：

 [HttpPost("uploadproductimage")]
        public async Task<ActionResult> UploadProductImage([FromForm] IFormFile image)
        {
            return Ok();
        }

此处出错，因为服务器需要参数“image”而不是“img：

formData.append("img", event);

 public async Task<ActionResult> UploadProductImage([FromForm] IFormFile image)

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