javaweb播放视频通过断点续传拖动滚动条

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/tongkaiming/article/details/82252061

java播放视频如果需要后台处理，并不是请求xxx.mp4.当需要拖动进度条的时候部分浏览器是不行的，这里就需要断点续传。

直接上代码，通过video的src请求

	/**
	 * video请求位置
	 * 
	 * @param request
	 * @param response
	 */
	@RequestMapping(value = "/player", method = RequestMethod.GET)
	public void player2(HttpServletRequest request, HttpServletResponse response) {
		String path = request.getServletContext().getRealPath("/static/my/video/interview.mp4");
		BufferedInputStream bis = null;
		try {
			File file = new File(path);
			if (file.exists()) {
				long p = 0L;
				long toLength = 0L;
				long contentLength = 0L;
				int rangeSwitch = 0; // 0,从头开始的全文下载；1,从某字节开始的下载（bytes=27000-）；2,从某字节开始到某字节结束的下载（bytes=27000-39000）
				long fileLength;
				String rangBytes = "";
				fileLength = file.length();

				// get file content
				InputStream ins = new FileInputStream(file);
				bis = new BufferedInputStream(ins);

				// tell the client to allow accept-ranges
				response.reset();
				response.setHeader("Accept-Ranges", "bytes");

				// client requests a file block download start byte
				String range = request.getHeader("Range");
				if (range != null && range.trim().length() > 0 && !"null".equals(range)) {
					response.setStatus(javax.servlet.http.HttpServletResponse.SC_PARTIAL_CONTENT);
					rangBytes = range.replaceAll("bytes=", "");
					if (rangBytes.endsWith("-")) { // bytes=270000-
						rangeSwitch = 1;
						p = Long.parseLong(rangBytes.substring(0, rangBytes.indexOf("-")));
						contentLength = fileLength - p; // 客户端请求的是270000之后的字节（包括bytes下标索引为270000的字节）
					} else { // bytes=270000-320000
						rangeSwitch = 2;
						String temp1 = rangBytes.substring(0, rangBytes.indexOf("-"));
						String temp2 = rangBytes.substring(rangBytes.indexOf("-") + 1, rangBytes.length());
						p = Long.parseLong(temp1);
						toLength = Long.parseLong(temp2);
						contentLength = toLength - p + 1; // 客户端请求的是 270000-320000 之间的字节
					}
				} else {
					contentLength = fileLength;
				}

				// 如果设设置了Content-Length，则客户端会自动进行多线程下载。如果不希望支持多线程，则不要设置这个参数。
				// Content-Length: [文件的总大小] - [客户端请求的下载的文件块的开始字节]
				response.setHeader("Content-Length", new Long(contentLength).toString());

				// 断点开始
				// 响应的格式是:
				// Content-Range: bytes [文件块的开始字节]-[文件的总大小 - 1]/[文件的总大小]
				if (rangeSwitch == 1) {
					String contentRange = new StringBuffer("bytes ").append(new Long(p).toString()).append("-")
							.append(new Long(fileLength - 1).toString()).append("/")
							.append(new Long(fileLength).toString()).toString();
					response.setHeader("Content-Range", contentRange);
					bis.skip(p);
				} else if (rangeSwitch == 2) {
					String contentRange = range.replace("=", " ") + "/" + new Long(fileLength).toString();
					response.setHeader("Content-Range", contentRange);
					bis.skip(p);
				} else {
					String contentRange = new StringBuffer("bytes ").append("0-").append(fileLength - 1).append("/")
							.append(fileLength).toString();
					response.setHeader("Content-Range", contentRange);
				}

				String fileName = file.getName();
				response.setContentType("application/octet-stream");
				response.addHeader("Content-Disposition", "attachment;filename=" + fileName);

				OutputStream out = response.getOutputStream();
				int n = 0;
				long readLength = 0;
				int bsize = 1024;
				byte[] bytes = new byte[bsize];
				if (rangeSwitch == 2) {
					// 针对 bytes=27000-39000 的请求，从27000开始写数据
					while (readLength <= contentLength - bsize) {
						n = bis.read(bytes);
						readLength += n;
						out.write(bytes, 0, n);
					}
					if (readLength <= contentLength) {
						n = bis.read(bytes, 0, (int) (contentLength - readLength));
						out.write(bytes, 0, n);
					}
				} else {
					while ((n = bis.read(bytes)) != -1) {
						out.write(bytes, 0, n);
					}
				}
				out.flush();
				out.close();
				bis.close();
			}
		} catch (IOException ie) {
			// 忽略 ClientAbortException 之类的异常
		} catch (Exception e) {
			e.printStackTrace();
		}
	}