Spring计时器StopWatch的简单使用_综合

最近新学了一个代码计时方法StopWatch替代繁琐的System.currentTimeMillis()计时，常见的工具类有org.springframework.util.StopWatch、org.apache.commons.lang3.time.StopWatch。（前者支持多任务执行时间统计，后者适用单任务计时）

1.org.springframework.util.StopWatch

源码解析：

public class StopWatch {/*** Identifier of this stop watch.* Handy when we have output from multiple stop watches* and need to distinguish between them in log or console output.*/private final String id;private boolean keepTaskList = true;private final List<TaskInfo> taskList = new LinkedList<>();/** Start time of the current task */private long startTimeMillis;/** Name of the current task */@Nullableprivate String currentTaskName;@Nullableprivate TaskInfo lastTaskInfo;private int taskCount;/** Total running time */private long totalTimeMillis;

...

可以看到源码中的 List<TaskInfo> taskList，用于存储一组任务的耗时时间。

比如：

// 定义一个计时器StopWatch stopWatch = new StopWatch("统一一组任务耗时");// 任务一耗时stopWatch.start("任务一");Thread.sleep(1000);stopWatch.stop();// 任务二耗时stopWatch.start("任务二");Thread.sleep(2000);stopWatch.stop();// 打印出所有任务耗时String result = stopWatch.prettyPrint();System.err.println(result);

执行结果：

StopWatch '统一一组任务耗时': running time (millis) = 3004
-----------------------------------------
ms % Task name
-----------------------------------------
01003 033% 任务一
02001 067% 任务二

2.org.apache.commons.lang3.time.StopWatch

// 统计执行时间
StopWatch duration = new StopWatch();
duration.start();//任务
Thread.sleep(2000);duration.stop();
System.err.println(duration.getTime(TimeUnit.MILLISECONDS));