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react实现文件下载

2026-01-26 20:09:35React

使用 `fetch` 或 `axios` 下载文件

通过 fetch 或 axios 请求文件数据，将响应转换为 Blob 对象，并创建下载链接。以下是一个示例代码：

const downloadFile = async (url, filename) => {
  try {
    const response = await fetch(url);
    const blob = await response.blob();
    const downloadUrl = window.URL.createObjectURL(blob);
    const link = document.createElement('a');
    link.href = downloadUrl;
    link.download = filename;
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    window.URL.revokeObjectURL(downloadUrl);
  } catch (error) {
    console.error('Error downloading file:', error);
  }
};

使用 `a` 标签直接下载

对于不需要鉴权的文件，可以直接通过 a 标签的 download 属性实现下载：

const downloadFile = (url, filename) => {
  const link = document.createElement('a');
  link.href = url;
  link.download = filename;
  document.body.appendChild(link);
  link.click();
  document.body.removeChild(link);
};

处理后端返回的文件流

如果后端返回文件流（如 PDF、Excel 等），可以通过设置响应类型为 blob 并处理：

const downloadFile = async (url, filename) => {
  try {
    const response = await axios.get(url, { responseType: 'blob' });
    const blob = new Blob([response.data]);
    const downloadUrl = window.URL.createObjectURL(blob);
    const link = document.createElement('a');
    link.href = downloadUrl;
    link.download = filename;
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    window.URL.revokeObjectURL(downloadUrl);
  } catch (error) {
    console.error('Error downloading file:', error);
  }
};

处理大文件分片下载

对于大文件，可以分片下载并合并：

const downloadLargeFile = async (url, filename) => {
  try {
    const response = await fetch(url);
    const reader = response.body.getReader();
    const chunks = [];
    let receivedLength = 0;

    while (true) {
      const { done, value } = await reader.read();
      if (done) break;
      chunks.push(value);
      receivedLength += value.length;
    }

    const blob = new Blob(chunks);
    const downloadUrl = window.URL.createObjectURL(blob);
    const link = document.createElement('a');
    link.href = downloadUrl;
    link.download = filename;
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    window.URL.revokeObjectURL(downloadUrl);
  } catch (error) {
    console.error('Error downloading large file:', error);
  }
};

添加下载进度提示

通过监听 axios 或 fetch 的进度事件，显示下载进度：

const downloadFileWithProgress = (url, filename) => {
  axios({
    url,
    method: 'GET',
    responseType: 'blob',
    onDownloadProgress: (progressEvent) => {
      const percentCompleted = Math.round(
        (progressEvent.loaded * 100) / progressEvent.total
      );
      console.log(`Download progress: ${percentCompleted}%`);
    },
  }).then((response) => {
    const blob = new Blob([response.data]);
    const downloadUrl = window.URL.createObjectURL(blob);
    const link = document.createElement('a');
    link.href = downloadUrl;
    link.download = filename;
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    window.URL.revokeObjectURL(downloadUrl);
  });
};