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vue大文件下载实现

2026-02-21 20:41:57VUE

Vue 大文件下载实现方案

前端分片下载

使用 axios 或 fetch 结合 Blob 对象实现分片下载，避免内存溢出。通过设置 Range 请求头控制下载范围。

async function downloadLargeFile(url, fileName) {
  const chunkSize = 1024 * 1024 * 5; // 5MB分片
  let startByte = 0;
  let endByte = chunkSize;
  const fileSize = await getFileSize(url); // 先获取文件总大小

  while (startByte < fileSize) {
    const response = await fetch(url, {
      headers: { 'Range': `bytes=${startByte}-${endByte}` }
    });
    const blob = await response.blob();
    saveChunk(blob, fileName, startByte === 0);
    startByte = endByte + 1;
    endByte = Math.min(startByte + chunkSize - 1, fileSize - 1);
  }
}

function saveChunk(blob, fileName, isFirstChunk) {
  const link = document.createElement('a');
  link.href = URL.createObjectURL(blob);
  link.download = fileName;
  link.style.display = 'none';
  document.body.appendChild(link);
  link.click();
  setTimeout(() => {
    URL.revokeObjectURL(link.href);
    document.body.removeChild(link);
  }, 100);
}

服务端配合

服务端需支持 Range 请求，返回 206 Partial Content 状态码。Node.js 示例：

app.get('/download', (req, res) => {
  const range = req.headers.range;
  const filePath = 'large-file.zip';
  const fileSize = fs.statSync(filePath).size;

  if (range) {
    const [start, end] = range.replace(/bytes=/, '').split('-');
    const chunkStart = parseInt(start, 10);
    const chunkEnd = end ? parseInt(end, 10) : fileSize - 1;

    res.writeHead(206, {
      'Content-Range': `bytes ${chunkStart}-${chunkEnd}/${fileSize}`,
      'Accept-Ranges': 'bytes',
      'Content-Length': chunkEnd - chunkStart + 1,
      'Content-Type': 'application/octet-stream'
    });

    fs.createReadStream(filePath, { start: chunkStart, end: chunkEnd })
      .pipe(res);
  } else {
    res.writeHead(200, {
      'Content-Length': fileSize,
      'Content-Type': 'application/octet-stream'
    });
    fs.createReadStream(filePath).pipe(res);
  }
});

进度显示优化

通过监听 onprogress 事件显示下载进度：

axios.get(url, {
  responseType: 'blob',
  onDownloadProgress: progressEvent => {
    const percent = Math.round(
      (progressEvent.loaded * 100) / progressEvent.total
    );
    console.log(`下载进度: ${percent}%`);
  }
}).then(response => {
  const url = window.URL.createObjectURL(new Blob([response.data]));
  const link = document.createElement('a');
  link.href = url;
  link.setAttribute('download', 'filename.ext');
  document.body.appendChild(link);
  link.click();
});

断点续传实现

利用 localStorage 存储已下载的字节位置：

let downloadedBytes = localStorage.getItem(fileName) || 0;

function resumeDownload(url, fileName) {
  const chunkSize = 1024 * 1024 * 5;
  let startByte = parseInt(downloadedBytes);
  let endByte = startByte + chunkSize - 1;

  fetch(url, {
    headers: { 'Range': `bytes=${startByte}-${endByte}` }
  }).then(response => {
    // ...处理分片
    localStorage.setItem(fileName, endByte + 1);
  });
}

Web Worker 处理

将耗时的下载逻辑放入 Web Worker 避免阻塞 UI：

vue大文件下载实现

// worker.js
self.onmessage = function(e) {
  const { url, fileName } = e.data;
  downloadLargeFile(url, fileName).then(() => {
    self.postMessage('done');
  });
};

// Vue组件中
const worker = new Worker('worker.js');
worker.postMessage({ url, fileName });
worker.onmessage = (e) => {
  if (e.data === 'done') console.log('下载完成');
};