Java web文件下載斷點續傳

一、下載文件請求 

    @RequestMapping(value = "/file/download")
    @ResponseBody
    public Res download(HttpServletRequest request, HttpServletResponse response) {


        File file = new File(request.getParameter("fileName"));
        if (file.exists()) {

            String range = request.getHeader("Range");
            if (range != null && (range = range.trim()).length() > 0) {
                Pattern rangePattern = Pattern.compile("^bytes=([0-9]+)-([0-9]+)?$");
                Matcher matcher = rangePattern.matcher(range);
                if (matcher.find()) {
                    Integer start = Integer.valueOf(matcher.group(1));
                    Integer end = 0;
                    String endStr = matcher.group(2);
                    if (endStr != null && (endStr = endStr.trim()).length() > 0)
                        end = Integer.valueOf(endStr);

                    downLoadByBreakpoint(file, start, end, response);
                    return null;
                }
            }

            downLoadAll(file, response);
            return null;
        }
        
        return Res.fail("文件不存在");

    }

 

二、斷點下載

 public void downLoadByBreakpoint(File file, long start, long end, HttpServletResponse response){
        OutputStream stream = null;
        RandomAccessFile fif = null;
        try {
            if (end <= 0) {
                end = file.length() - 1;
            }
            stream = response.getOutputStream();
            response.reset();
            response.setStatus(206);
            response.setContentType("application/octet-stream");
            response.setHeader("Content-disposition", "attachment; filename=" + file.getName());
            response.setHeader("Content-Length", String.valueOf(end - start + 1));
            response.setHeader("Accept-Ranges", "bytes");
            response.setHeader("Content-Range", String.format("bytes %s-%s/%s", start, end, file.length()));
            fif = new RandomAccessFile(file, "r");
            fif.seek(start);
            long index = start;
            int d;
            byte[] buf = new byte[10240];
            while (index <= end && (d = fif.read(buf)) != -1) {
                if (index + d > end) {
                    d = (int)(end - index + 1);
                }
                index += d;
                stream.write(buf, 0, d);
            }
            stream.flush();
        } catch (Exception e) {
            try {
                if (stream != null)
                    stream.close();
                if (fif != null)
                    fif.close();
            } catch (Exception e11) {
            }
        }
    }

 

三、普通全量下載

    public void downLoadAll(File file, HttpServletResponse response){
        OutputStream stream = null;
        BufferedInputStream fif = null;
        try {
            stream = response.getOutputStream();
            response.reset();
            response.setContentType("application/octet-stream");
            response.setHeader("Content-disposition", "attachment; filename=" + file.getName());
            response.setHeader("Content-Length", String.valueOf(file.length()));
            fif = new BufferedInputStream(new FileInputStream(file));
            int d;
            byte[] buf = new byte[10240];
            while ((d = fif.read(buf)) != -1) {
                stream.write(buf, 0, d);
            }
            stream.flush();
        } catch (Exception e) {
            try {
                if (stream != null)
                    stream.close();
                if (fif != null)
                    fif.close();
            } catch (Exception e11) {
            }
        }
    }