监听耗时-StopWatch

        // Spring的StopWatch
       // 但其实如果自己封装的话，可以做得更简洁一点；
        StopWatch stopWatch = new StopWatch();
        stopWatch.start("task1");
        Thread.sleep(1000L);
        stopWatch.stop();
        long task1Cost = stopWatch.getLastTaskTimeMillis();

        stopWatch.start("task2");
        Thread.sleep(1000L);
        stopWatch.stop();
        long task2Cost = stopWatch.getLastTaskTimeMillis();
        long totalCost = stopWatch.getTotalTimeMillis();
        System.out.println("task1Cost:" + task1Cost + ",task2Cost:" + task2Cost + ",totalCost:" + totalCost);