StopWatch 监控Java代码运行时间和分析性能

我们在日常进行Java语言开发时，可能需要监控不同方法的运行时间，知道性能瓶颈在哪。利用springframework框架的工具类StopWatch可以快速方便的查看到每段代码运行的时间，准确确定性能瓶颈所在。

使用StopWatch类也很简单。new出实例，调用该实例的start（）和stop（）方法即可。如下代码

StopWatch stopWatch = new StopWatch();//房间类型图片List<ImageData> images = platenoHotelService.getHotelImage(innId, 2);Map<String, String> imageUrl = new HashMap<>();if (images !=null) {for (ImageData image : images) {imageUrl.put(image.getRoomTypeCode(), image.getImageUrl());}}//调用酒店房型列表stopWatch.start("search.getHotelRoomType");String roomType = platenoHotelService.getHotelRoomType(innId);stopWatch.stop();stopWatch.start("search.parseObject");JSONObject roomTypeList = JSONObject.parseObject(roomType);JSONArray roomTypeArray = roomTypeList.getJSONObject("data").getJSONArray("roomTypeData");stopWatch.stop();List<HotelRoomTypeVO> hotelRoomTypeVOList = new ArrayList<>();stopWatch.start("search.roomTypeArrayForeach");for (Object roomTypeItem : roomTypeArray) {JSONObject roomTypeObject = (JSONObject)roomTypeItem;HotelRoomTypeVO hotelRoom = JSONObject.toJavaObject(roomTypeObject, HotelRoomTypeVO.class);if(hotelRoom.getValid() == 1) {RealRoomStatusData realRoomStatusData = platenoHotelService.getHotelRoomInfo(innId, hotelRoom.getRoomTypeCode(), endOfDay, sourceType, days);if (realRoomStatusData != null) {hotelRoom.setImageUrl(imageUrl.get(hotelRoom.getRoomTypeCode()));hotelRoom.setRealRoomStatusData(realRoomStatusData);hotelRoomTypeVOList.add(hotelRoom);}}}stopWatch.stop();logger.info("[酒店房型列表耗时：]" + stopWatch.prettyPrint());

为了查看结果，调用prettyPrint()方法即可，下图就是上面示例的运行结果。可以看出总花费时间6062ms。三列分别为监控代码段的花费时间（毫秒）、百分比、名称。可以很直观看出每段代码的运行时间以及所占比分比，帮助我们快速找到主要性能问题。