稍微改进了下代码

[mianqiangsheng]

首先对up主的代码表达敬意，然后我自己小改了下，实现针对特别小的文件下载也支持。修改DownloadMain的splitDownload()方法：

/**
     * 切分下载任务到多个线程
     *
     * @param url
     * @param futureList
     * @throws IOException
     */
    public void splitDownload(String url, List<Future<Boolean>> futureList) throws IOException {
        long httpFileContentLength = HttpUtls.getHttpFileContentLength(url);
        // 任务切分
        long size = httpFileContentLength / DOWNLOAD_THREAD_NUM;
        long lastSize = httpFileContentLength - (size * (DOWNLOAD_THREAD_NUM - 1));

        /**
         * 针对超小的文件，仅启动一个线程来下载
         */
        if (size == 0){
            DOWNLOAD_THREAD_NUM = 1;
            ExecutorService executor = Executors.newFixedThreadPool(DOWNLOAD_THREAD_NUM + 1);
            DownloadThread downloadThread = new DownloadThread(url, 0, lastSize, 0, httpFileContentLength);
            Future<Boolean> future = executor.submit(downloadThread);
            futureList.add(future);
        }else {
            for (int i = 0; i < DOWNLOAD_THREAD_NUM; i++) {
                long start = i * size;
                Long downloadWindow = (i == DOWNLOAD_THREAD_NUM - 1) ? lastSize : size;
                Long end = start + downloadWindow;
                if (start != 0) {
                    start++;
                }
                DownloadThread downloadThread = new DownloadThread(url, start, end, i, httpFileContentLength);
                Future<Boolean> future = executor.submit(downloadThread);
                futureList.add(future);
            }
        }


    }

[程序猿阿朗]

感谢😀，之前确实没有考虑到文件小到不能切分的情况，代码收下了，后面把这个项目优化下，把小文件逻辑也整合进去哈