spring boot断点续传

最新推荐文章于 2025-04-02 07:23:35 发布

原创最新推荐文章于 2025-04-02 07:23:35 发布 · 887 阅读

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#spring boot #java #后端

本文介绍了一个使用Spring MVC实现的文件下载API。该API支持HTTP范围请求，能够处理从指定位置开始的部分文件下载，并正确设置HTTP响应头以允许客户端续传或断点下载。通过示例代码展示了如何使用Java NIO进行高效的数据传输。

@GetMapping("/download")
public void download(@RequestParam String path, HttpServletRequest request, HttpServletResponse response) throws IOException {
    Path downloadFile = Paths.get(path);
    if (!Files.exists(downloadFile)) {
        response.setStatus(HttpStatus.NOT_FOUND.value());
        return;
    }
    long fromPos = 0;
    long downloadSize = Files.size(downloadFile);
    if (request.getHeader("Range") != null) {
        response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT);
        String[] ary = request.getHeader("Range").replaceAll("bytes=", "").split("-");
        fromPos = Long.parseLong(ary[0]);
        downloadSize = (ary.length < 2 ? downloadSize : Long.parseLong(ary[1])) - fromPos;
    }
    response.setContentType(MediaType.APPLICATION_OCTET_STREAM_VALUE);
    response.setContentLengthLong(downloadSize);
    response.setHeader("Content-Disposition", String.format("attachment; filename=\"%s\"", downloadFile.getFileName().toString()));
    response.setHeader("Accept-Ranges", "bytes");
    response.setHeader("Content-Range", String.format("bytes %s-%s/%s", fromPos, (fromPos + downloadSize), Files.size(downloadFile)));

    try (FileChannel inChannel = FileChannel.open(downloadFile);
         WritableByteChannel outChannel = Channels.newChannel(response.getOutputStream())) {
        while (downloadSize > 0) {
            long count = inChannel.transferTo(fromPos, downloadSize, outChannel);
            if (count > 0) {
                fromPos += count;
                downloadSize -= count;
            }
        }

    }
}