导出文件

int pageSize = 20000;
                // 整数除
                int totalPage = total / pageSize;

                // 余数
                int surplus = total % pageSize;
                if (surplus > 0) {
                    ++totalPage;
                }
//创建文件
                ExportUtil.createFile(exportFilename);
                FileOutputStream fos = null;
                BufferedOutputStream bos = null;
                StringBuffer sb = new StringBuffer("");
//添加头标题
                ExportUtil.addTitle(sb);
                String filename = ExportUtil.getExportPath() + exportFilename;
                try {
                    fos = new FileOutputStream(filename);
                    bos = new BufferedOutputStream(fos);
                    for (int i = 1; i <= totalPage; i++) {
                        QueryResult<OmsAlarm> result =
                            historyService.queryHistoricalAlarm(cond,
                                    pageSize,
                                    i);
                        List<OmsAlarm> list = result.getObjectList();
                        ExportUtil.addToStringBuffer(list, sb);
                        IOUtils.write(sb, bos, ENCODING);
                        sb.delete(0, sb.length());
                        list.clear();
                        curAlarmList.clear();
                    }
                } catch (IOException e) {
                    LOGGER.error("export faild", e);
                } finally {
                    IOUtils.closeQuietly(bos);
                    IOUtils.closeQuietly(fos);
                }
                ExportUtil.downFile(export, exportFilename, filename);
                long endExport = System.currentTimeMillis();
                long timeExport = endExport - start;
                LOGGER.debug("history  export total time:" + timeExport);