let fileChunkList = []; //存放文件切片
let cur = 0;
// 分片
while(cur < file.size){
  fileChunkList.push(file.slice(cur,cur + chunkSize));
  cur += chunkSize;
}

function handleBeforeUpload(file) {
  const chunkSize = 1024 * 1024 * 10; // 10MB
  // 計(jì)算md5
  md5(file, chunkSize).then(md5 => {
    //檢查是否秒傳
    request({
      url: "/upload/check/" + md5,
      method: "get",
    }).then(result => {
      const isOk = result.isOk;
      const haveList2 = result.haveList; //已經(jīng)上傳的分片下標(biāo)
      if(isOk) {
        console.log("秒傳成功");
        return;
      }
      haveList.value = haveList2;
      let chunkIndex = 0;
      //上傳第一個(gè)分片
      upload(fileChunkList.value, chunkIndex, md5, file);
    })
  });
  return false;
}

/**
 * 分片文件上傳
 * @param file 文件
 * @param chunkIndex 分片下標(biāo)
 * @param md5 md5
 * @param totalFileSize 文件總大小
 * @param fileName 文件名
 */
@PostMapping("/shard")
public AjaxResult shardUpload(@RequestParam MultipartFile file, @RequestParam Integer chunkIndex,
                              @RequestParam String md5, @RequestParam Long totalFileSize,
                              @RequestParam String fileName) throws Exception{
    // 存放文件目錄
    String dirPath = System.getProperty("user.dir") + "/file/"+md5+"/";
    File dirFile = new File(dirPath);
    if(!dirFile.exists()){
        dirFile.mkdir();
    }
    File tempFile = new File(dirPath + fileName);
    RandomAccessFile rw = new RandomAccessFile(tempFile, "rw");
    // 定位到分片的偏移量
    rw.seek(CHUNK_SIZE * chunkIndex);
    // 寫入分片數(shù)據(jù)
    rw.write(file.getBytes());
    // 關(guān)閉流
    rw.close();
    // 讀取已經(jīng)分片集合
    List<Object> hasChunkList;
    String hasChunkKey = CHUNK_PREFIX + md5;
    if(redisCache.hasKey(hasChunkKey)){
        hasChunkList = redisCache.getCacheList(hasChunkKey);
    } else {
        hasChunkList = new ArrayList<>();
    }
    hasChunkList.add(chunkIndex);
    // 將最新的分片下標(biāo)更新到Redis中
    redisCache.addCacheListOne(hasChunkKey,chunkIndex);
    // 判斷是否上傳完成
    int totalNeedChunks = (int) Math.ceil((double) totalFileSize / CHUNK_SIZE);
    // 總共需要的分片數(shù) 和 已經(jīng)分片上傳的數(shù)量相等 則上傳完成
    boolean isOk = totalNeedChunks == hasChunkList.size();
    if(isOk){
        redisCache.setCacheObject(UPLOAD_ISOK_PREFIX + md5, true);
    }
    AjaxResult ajax = AjaxResult.success();
    ajax.put("hasChunkList",hasChunkList);
    ajax.put("isOk",isOk);
    return ajax;
}