断点续传下载

最近写的一个断点下载功能代码，支持迅雷，旋风，IE等下载。迅雷、旋风测试正常，代码如下：

request.setCharacterEncoding("UTF-8");
		String primary = request.getParameter("primary");
		String uid = request.getParameter("uid");
		String timestamp = request.getParameter("timestamp");
		String verify = request.getParameter("verify");
//校验下载权限
		String verify_n = MD5.md5(uid + primary + "lyjilu" + timestamp);
		if (!verify_n.equals(verify)) {
			response.sendError(HttpServletResponse.SC_NOT_FOUND);
			return;
		}
		
		response.reset();
		String filePath = ZipAssist.getZipPath(primary);
		File file = new File(filePath);
		if(!file.exists() || !file.isFile()){
			response.sendError(HttpServletResponse.SC_NOT_FOUND);
			return;
		}
		String range = request.getHeader("range");
		long fileLen = file.length();
		long begin = 0;
		long end = fileLen - 1;
		String contentRange = null;
		if (range != null) {
			//设置状态
			response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT);
			//得到请求byte范围
			String rangeBytes = range.replace("bytes=", "");
			String[] rangeArr = rangeBytes.trim().split("-");
			begin = Long.parseLong(rangeArr[0]);
//			如果请求有结束范围  eg:1024000-2058220
			if (rangeArr.length > 1) {
				end = Long.parseLong(rangeArr[1]);
			}
			contentRange = new StringBuffer("bytes ").append(begin).append("-")
					.append(end).append("/").append(fileLen).toString();
		}
//		设置响应信息
		response.setContentType("application/octet-stream; charset=utf-8");
		response.setHeader("Accept-Ranges", "bytes");
		response.setHeader("Content-Range", contentRange);
		request.setCharacterEncoding("UTF-8");
		response.addHeader(
				"Content-Disposition",
				"attachment;filename="
						+ new String(filePath.substring(
								filePath.lastIndexOf(File.separator) + 1)
								.getBytes("gb2312"), "ISO8859-1"));
		response.addHeader("Content-Length", String.valueOf(end + 1 - begin));
		ServletOutputStream out = null;
		RandomAccessFile randomf = null;
		try {
			randomf = new RandomAccessFile(file, "r");
			out = response.getOutputStream();
			byte[] bt = new byte[1024 * 1024];
			int i = -1;
			try {
//				读取数据
				randomf.seek(begin);
				while ((i = randomf.read(bt)) != -1) {
					if (randomf.getFilePointer() >= end) {
						out.write(bt, 0,
								(int) (i + end - randomf.getFilePointer() + 1));
						break;
					} else
						out.write(bt, 0, i);
				}
				out.flush();
			} catch (Exception e) {
				System.out.println("下载报错：" + e.toString());
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				randomf.close();
			} catch (Exception e) {
			}
			if (out != null)
				out.close();
		}

	}

 只支持：请求range为

1:null

2:xxxxxxx-

3:xxxxxxx-yyyyyyyyy