文件分块+断点续传 实现大文件上传全栈解决方案（前端+nodejs）

前端代码实现文件分块并使用FormData发送给Node.js服务器，服务器端接收文件块并写入磁盘，最后合并文件块。

// 前端JavaScript代码
 
// 文件分块上传函数
function uploadFileInChunks(file, chunkSize = 1024 * 1024, uploadUrl) {
  let fileSize = file.size;
  let chunkCount = Math.ceil(fileSize / chunkSize);
 
  let start = 0;
  let end = chunkSize;
 
  for (let i = 0; i < chunkCount; i++) {
    let chunk = file.slice(start, end);
    let formData = new FormData();
    formData.append('file', chunk);
    formData.append('filename', file.name);
    formData.append('chunkIndex', i);
    formData.append('chunkCount', chunkCount);
 
    fetch(uploadUrl, {
      method: 'POST',
      body: formData
    })
    .then(response => response.json())
    .then(data => {
      if (data.success) {
        console.log('Chunk uploaded successfully');
      } else {
        console.error('Error uploading chunk');
      }
    })
    .catch(error => console.error('Error:', error));
 
    start = end;
    end = start + chunkSize;
  }
}
 
// 使用示例
const inputElement = document.getElementById('fileInput');
inputElement.addEventListener('change', function(e) {
  const file = e.target.files[0];
  const uploadUrl = 'http://yourserver.com/upload'; // Node.js服务器地址
  uploadFileInChunks(file, 1024 * 1024, uploadUrl); // 每个块大小为1MB
});

Node.js服务器端代码：

// Node.js + Express代码
const express = require('express');
const fs = require('fs');
const multer = require('multer');
const path = require('path');
const app = express();
 
const storage = multer.diskStorage({
  destination: function (req, file, cb) {
    let folder = 'uploads/' + req.body.filename;
    if (!fs.existsSync(folder)) {
      fs.mkdirSync(folder, { recursive: true });
    }
    cb(null, folder)
  },
  filename: function (req, file, cb) {
    cb(null, file.fieldname + '-' + req.body.chunkIndex)
  }
})
 
const upload = multer({ storage: storage });
 
app.post('/upload', upload.single('file'), function (req, res) {
  let fileIndex = req.body.chunkIndex;
  let fileName = req.body.filename;
  let chunkCount = req.body.chunkCount;
  let fileChunk = req.file.path;
 
  // 合并文件逻辑（简化版）
  if (checkIfAllChunksPresent(fileName, chunkCount)) {
    conc