Java video playback with breakpoints to achieve no lag

Background: The front-end usually displays the page and loads the video from the beginning. This will cause poor user performance. If the network speed is not good, fast forwarding will freeze and the loading will be too slow. In order to solve this problem, the backend provides an interface for the front-end. Need to implement breakpoint download function

@ApiOperation(value = "视频播放一方法", notes = "视频播放一方法")
    @GetMapping(value = "/preview")
    @ApiImplicitParams({
            @ApiImplicitParam(name = "url", value = "文件路径", required = true,paramType = "query")
    })
    @Override
    public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException {
        // TODO Auto-generated method stub
        HttpServletRequest request=(HttpServletRequest)req;
        HttpServletResponse response=(HttpServletResponse)res;
        System.out.println(req.getParameter("url"));
        String path = addMinioUrl.getObPath(req.getParameter("url"));
        //String path="E:/video/111.mp4";
        RandomAccessFile targetFile = null;
        OutputStream outputStream = null;
        try {
            outputStream = response.getOutputStream();
            response.reset();
            //获取请求头中Range的值
            String rangeString = request.getHeader(HttpHeaders.RANGE);

            //打开文件
            File file = new File(path);
            if (file.exists()) {
                //使用RandomAccessFile读取文件
                targetFile = new RandomAccessFile(file, "r");
                long fileLength = targetFile.length();
                long requestSize = (int) fileLength;
                //分段下载视频
                if (StringUtils.hasText(rangeString)) {
                    //从Range中提取需要获取数据的开始和结束位置
                    long requestStart = 0, requestEnd = 0;
                    String[] ranges = rangeString.split("=");
                    if (ranges.length > 1) {
                        String[] rangeDatas = ranges[1].split("-");
                        requestStart = Integer.parseInt(rangeDatas[0]);
                        if (rangeDatas.length > 1) {
                            requestEnd = Integer.parseInt(rangeDatas[1]);
                        }
                    }
                    if (requestEnd != 0 && requestEnd > requestStart) {
                        requestSize = requestEnd - requestStart + 1;
                    }
                    //根据协议设置请求头
                    response.setHeader(HttpHeaders.ACCEPT_RANGES, "bytes");
                    response.setHeader(HttpHeaders.CONTENT_TYPE, "video/mp4");
                    if (!StringUtils.hasText(rangeString)) {
                        response.setHeader(HttpHeaders.CONTENT_LENGTH, fileLength + "");
                    } else {
                        long length;
                        if (requestEnd > 0) {
                            length = requestEnd - requestStart + 1;
                            response.setHeader(HttpHeaders.CONTENT_LENGTH, "" + length);
                            response.setHeader(HttpHeaders.CONTENT_RANGE, "bytes " + requestStart + "-" + requestEnd + "/" + fileLength);
                        } else {
                            length = fileLength - requestStart;
                            response.setHeader(HttpHeaders.CONTENT_LENGTH, "" + length);
                            response.setHeader(HttpHeaders.CONTENT_RANGE, "bytes " + requestStart + "-" + (fileLength - 1) + "/"
                                    + fileLength);
                        }
                    }
                    //断点传输下载视频返回206
                    response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT);
                    //设置targetFile，从自定义位置开始读取数据
                    targetFile.seek(requestStart);
                } else {
                    //如果Range为空则下载整个视频
                    response.setHeader(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=test.mp4");
                    //设置文件长度
                    response.setHeader(HttpHeaders.CONTENT_LENGTH, String.valueOf(fileLength));
                }

                //从磁盘读取数据流返回
                byte[] cache = new byte[4096];
                try {
                    while (requestSize > 0) {
                        int len = targetFile.read(cache);
                        if (requestSize < cache.length) {
                            outputStream.write(cache, 0, (int) requestSize);
                        } else {
                            outputStream.write(cache, 0, len);
                            if (len < cache.length) {
                                break;
                            }
                        }
                        requestSize -= cache.length;
                    }
                } catch (IOException e) {
                    // tomcat原话。写操作IO异常几乎总是由于客户端主动关闭连接导致，所以直接吃掉异常打日志
                    //比如使用video播放视频时经常会发送Range为0- 的范围只是为了获取视频大小，之后就中断连接了
                    //log.info(e.getMessage());
                    //throw new RuntimeException(e);
                }
            } else {
                // throw new RuntimeException("文件路劲有误");
            }
            outputStream.flush();
        } catch (Exception e) {
            // e.printStackTrace();
            // throw new RuntimeException("文件传输错误");
        }finally {
            if(outputStream != null){
                try {
                    outputStream.close();
                } catch (IOException e) {
                    //e.printStackTrace();
                    // throw new RuntimeException("流释放错误");

                }
            }
            if(targetFile != null){
                try {
                    targetFile.close();
                } catch (IOException e) {
                    //e.printStackTrace();
                    //    throw new RuntimeException("文件流释放错误");
                }
            }
        }

    }

You need to install a video plug-in on the front end. If you need it, you can @ me