计时器StopWatch的几种写法

下面提供三种计时器的写法供大家参考，大家可以自行选择自己钟爱的使用。

写法一（Spring 包提供的计时器）：

 import java.text.NumberFormat;
 import java.util.LinkedList;
 import java.util.List;

 /**
  * Simple stop watch, allowing for timing of a number of tasks,
  * exposing total running time and running time for each named task.
  *
  * <p>Conceals use of {@code System.currentTimeMillis()}, improving the
  * readability of application code and reducing the likelihood of calculation errors.
  *
  * <p>Note that this object is not designed to be thread-safe and does not
  * use synchronization.
  *
  * <p>This class is normally used to verify performance during proof-of-concepts
  * and in development, rather than as part of production applications.
  *
  * @author Rod Johnson
  * @author Juergen Hoeller
  * @author Sam Brannen
  * @since May 2, 2001
  */
 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<TaskInfo>();

     /** Start time of the current task */
     private long startTimeMillis;

     /** Is the stop watch currently running? */
     private boolean running;

     /** Name of the current task */
     private String currentTaskName;

     private TaskInfo lastTaskInfo;

     private int taskCount;

     /** Total running time */
     private long totalTimeMillis;

     /**
      * Construct a new stop watch. Does not start any task.
      */
     public StopWatch() {
         this("");
     }

     /**
      * Construct a new stop watch with the given id.
      * Does not start any task.
      * @param id identifier for this stop watch.
      * Handy when we have output from multiple stop watches
      * and need to distinguish between them.
      */
     public StopWatch(String id) {
         this.id = id;
     }

     /**
      * Return the id of this stop watch, as specified on construction.
      * @return the id (empty String by default)
      * @since 4.2.2
      * @see #StopWatch(String)
      */
     public String getId() {
         return this.id;
     }

     /**
      * Determine whether the TaskInfo array is built over time. Set this to
      * "false" when using a StopWatch for millions of intervals, or the task
      * info structure will consume excessive memory. Default is "true".
      */
     public void setKeepTaskList(boolean keepTaskList) {
         this.keepTaskList = keepTaskList;
     }

     /**
      * Start an unnamed task. The results are undefined if {@link #stop()}
      * or timing methods are called without invoking this method.
      * @see #stop()
      */
     public void start() throws IllegalStateException {
         start("");
     }

     /**
      * Start a named task. The results are undefined if {@link #stop()}
      * or timing methods are called without invoking this method.
      * @param taskName the name of the task to start
      * @see #stop()
      */
     public void start(String taskName) throws IllegalStateException {
         if (this.running) {
             throw new IllegalStateException("Can't start StopWatch: it's already running");
         }
         this.running = true;
         this.currentTaskName = taskName;
         this.startTimeMillis = System.currentTimeMillis();
     }

     /**
      * Stop the current task. The results are undefined if timing
      * methods are called without invoking at least one pair
      * {@code start()} / {@code stop()} methods.
      * @see #start()
      */
     public void stop() throws IllegalStateException {
         if (!this.running) {
             throw new IllegalStateException("Can't stop StopWatch: it's not running");
         }
         long lastTime = System.currentTimeMillis() - this.startTimeMillis;
         this.totalTimeMillis += lastTime;
         this.lastTaskInfo = new TaskInfo(this.currentTaskName, lastTime);
         if (this.keepTaskList) {
             this.taskList.add(lastTaskInfo);
         }
         ++this.taskCount;
         this.running = false;
         this.currentTaskName = null;
     }

     /**
      * Return whether the stop watch is currently running.
      * @see #currentTaskName()
      */
     public boolean isRunning() {
         return this.running;
     }

     /**
      * Return the name of the currently running task, if any.
      * @since 4.2.2
      * @see #isRunning()
      */
     public String currentTaskName() {
         return this.currentTaskName;
     }

     /**
      * Return the time taken by the last task.
      */
     public long getLastTaskTimeMillis() throws IllegalStateException {
         if (this.lastTaskInfo == null) {
             throw new IllegalStateException("No tasks run: can't get last task interval");
         }
         return this.lastTaskInfo.getTimeMillis();
     }

     /**
      * Return the name of the last task.
      */
     public String getLastTaskName() throws IllegalStateException {
         if (this.lastTaskInfo == null) {
             throw new IllegalStateException("No tasks run: can't get last task name");
         }
         return this.lastTaskInfo.getTaskName();
     }

     /**
      * Return the last task as a TaskInfo object.
      */
     public TaskInfo getLastTaskInfo() throws IllegalStateException {
         if (this.lastTaskInfo == null) {
             throw new IllegalStateException("No tasks run: can't get last task info");
         }
         return this.lastTaskInfo;
     }

     /**
      * Return the total time in milliseconds for all tasks.
      */
     public long getTotalTimeMillis() {
         return this.totalTimeMillis;
     }

     /**
      * Return the total time in seconds for all tasks.
      */
     public double getTotalTimeSeconds() {
         return this.totalTimeMillis / 1000.0;
     }

     /**
      * Return the number of tasks timed.
      */
     public int getTaskCount() {
         return this.taskCount;
     }

     /**
      * Return an array of the data for tasks performed.
      */
     public TaskInfo[] getTaskInfo() {
         if (!this.keepTaskList) {
             throw new UnsupportedOperationException("Task info is not being kept!");
         }
         return this.taskList.toArray(new TaskInfo[this.taskList.size()]);
     }

     /**
      * Return a short description of the total running time.
      */
     public String shortSummary() {
         return "StopWatch '" + getId() + "': running time (millis) = " + getTotalTimeMillis();
     }

     /**
      * Return a string with a table describing all tasks performed.
      * For custom reporting, call getTaskInfo() and use the task info directly.
      */
     public String prettyPrint() {
         StringBuilder sb = new StringBuilder(shortSummary());
         sb.append('\n');
         if (!this.keepTaskList) {
             sb.append("No task info kept");
         }
         else {
             sb.append("-----------------------------------------\n");
             sb.append("ms     %     Task name\n");
             sb.append("-----------------------------------------\n");
             NumberFormat nf = NumberFormat.getNumberInstance();
             nf.setMinimumIntegerDigits(5);
             nf.setGroupingUsed(false);
             NumberFormat pf = NumberFormat.getPercentInstance();
             pf.setMinimumIntegerDigits(3);
             pf.setGroupingUsed(false);
             for (TaskInfo task : getTaskInfo()) {
                 sb.append(nf.format(task.getTimeMillis())).append("  ");
                 sb.append(pf.format(task.getTimeSeconds() / getTotalTimeSeconds())).append("  ");
                 sb.append(task.getTaskName()).append("\n");
             }
         }
         return sb.toString();
     }

     /**
      * Return an informative string describing all tasks performed
      * For custom reporting, call {@code getTaskInfo()} and use the task info directly.
      */
     @Override
     public String toString() {
         StringBuilder sb = new StringBuilder(shortSummary());
         if (this.keepTaskList) {
             for (TaskInfo task : getTaskInfo()) {
                 sb.append("; [").append(task.getTaskName()).append("] took ").append(task.getTimeMillis());
                 long percent = Math.round((100.0 * task.getTimeSeconds()) / getTotalTimeSeconds());
                 sb.append(" = ").append(percent).append("%");
             }
         }
         else {
             sb.append("; no task info kept");
         }
         return sb.toString();
     }

     /**
      * Inner class to hold data about one task executed within the stop watch.
      */
     public static final class TaskInfo {

         private final String taskName;

         private final long timeMillis;

         TaskInfo(String taskName, long timeMillis) {
             this.taskName = taskName;
             this.timeMillis = timeMillis;
         }

         /**
          * Return the name of this task.
          */
         public String getTaskName() {
             return this.taskName;
         }

         /**
          * Return the time in milliseconds this task took.
          */
         public long getTimeMillis() {
             return this.timeMillis;
         }

         /**
          * Return the time in seconds this task took.
          */
         public double getTimeSeconds() {
             return (this.timeMillis / 1000.0);
         }
     }

 }

下面写一个调用：

public static void main(String[] args) throws InterruptedException {
//        StopWatchTest.test0();
     StopWatchTest.test1();
}

public static void test1() throws InterruptedException {
     StopWatch sw = new StopWatch("test");
     sw.start("task1");
     // do something
    Thread.sleep(100);
    sw.stop();
    sw.start("task2");
    // do something
    Thread.sleep(200);
    sw.stop();
    System.out.println("sw.prettyPrint()~~~~~~~~~~~~~~~~~");
    System.out.println(sw.prettyPrint());
}

运行结果：
sw.prettyPrint()~~~~~~~~~~~~~~~~~
StopWatch 'test': running time (millis) = 308
-----------------------------------------
ms     %     Task name
-----------------------------------------
00104  034%  task1
00204  066%  task2
---------------------

　　start开始记录，stop停止记录，然后通过StopWatch的prettyPrint方法，可直观的输出代码执行耗时，以及执行时间百分比，瞬间感觉比之前的方式高大上了一个档次。

 除此之外，还有以下两个方法shortSummary,getTotalTimeMillis，查看程序执行时间。

写法二（apache.commons实现的计时器）：

import java.util.concurrent.TimeUnit;

/**
 * <p>
 * <code>StopWatch</code> provides a convenient API for timings.
 * </p>
 *
 * <p>
 * To start the watch, call {@link #start()} or {@link StopWatch#createStarted()}. At this point you can:
 * </p>
 * <ul>
 * <li>{@link #split()} the watch to get the time whilst the watch continues in the background. {@link #unsplit()} will
 * remove the effect of the split. At this point, these three options are available again.</li>
 * <li>{@link #suspend()} the watch to pause it. {@link #resume()} allows the watch to continue. Any time between the
 * suspend and resume will not be counted in the total. At this point, these three options are available again.</li>
 * <li>{@link #stop()} the watch to complete the timing session.</li>
 * </ul>
 *
 * <p>
 * It is intended that the output methods {@link #toString()} and {@link #getTime()} should only be called after stop,
 * split or suspend, however a suitable result will be returned at other points.
 * </p>
 *
 * <p>
 * NOTE: As from v2.1, the methods protect against inappropriate calls. Thus you cannot now call stop before start,
 * resume before suspend or unsplit before split.
 * </p>
 *
 * <p>
 * 1. split(), suspend(), or stop() cannot be invoked twice<br>
 * 2. unsplit() may only be called if the watch has been split()<br>
 * 3. resume() may only be called if the watch has been suspend()<br>
 * 4. start() cannot be called twice without calling reset()
 * </p>
 *
 * <p>This class is not thread-safe</p>
 *
 * @since 2.0
 */
public class StopWatch {

    private static final long NANO_2_MILLIS = 1000000L;

    /**
     * Provides a started stopwatch for convenience.
     *
     * @return StopWatch a stopwatch that's already been started.
     *
     * @since 3.5
     */
    public static StopWatch createStarted() {
        final StopWatch sw = new StopWatch();
        sw.start();
        return sw;
    }

    /**
     * Enumeration type which indicates the status of stopwatch.
     */
    private enum State {

        UNSTARTED {
            @Override
            boolean isStarted() {
                return false;
            }
            @Override
            boolean isStopped() {
                return true;
            }
            @Override
            boolean isSuspended() {
                return false;
            }
        },
        RUNNING {
            @Override
            boolean isStarted() {
                return true;
            }
            @Override
            boolean isStopped() {
                return false;
            }
            @Override
            boolean isSuspended() {
                return false;
            }
        },
        STOPPED {
            @Override
            boolean isStarted() {
                return false;
            }
            @Override
            boolean isStopped() {
                return true;
            }
            @Override
            boolean isSuspended() {
                return false;
            }
        },
        SUSPENDED {
            @Override
            boolean isStarted() {
                return true;
            }
            @Override
            boolean isStopped() {
                return false;
            }
            @Override
            boolean isSuspended() {
                return true;
            }
        };

        /**
         * <p>
         * The method is used to find out if the StopWatch is started. A suspended
         * StopWatch is also started watch.
         * </p>

         * @return boolean
         *             If the StopWatch is started.
         */
        abstract boolean isStarted();

        /**
         * <p>
         * This method is used to find out whether the StopWatch is stopped. The
         * stopwatch which's not yet started and explicitly stopped stopwatch is
         * considered as stopped.
         * </p>
         *
         * @return boolean
         *             If the StopWatch is stopped.
         */
        abstract boolean isStopped();

        /**
         * <p>
         * This method is used to find out whether the StopWatch is suspended.
         * </p>
         *
         * @return boolean
         *             If the StopWatch is suspended.
         */
        abstract boolean isSuspended();
    }

    /**
     * Enumeration type which indicates the split status of stopwatch.
     */
    private enum SplitState {
        SPLIT,
        UNSPLIT
    }
    /**
     * The current running state of the StopWatch.
     */
    private State runningState = State.UNSTARTED;

    /**
     * Whether the stopwatch has a split time recorded.
     */
    private SplitState splitState = SplitState.UNSPLIT;

    /**
     * The start time.
     */
    private long startTime;

    /**
     * The start time in Millis - nanoTime is only for elapsed time so we
     * need to also store the currentTimeMillis to maintain the old
     * getStartTime API.
     */
    private long startTimeMillis;

    /**
     * The stop time.
     */
    private long stopTime;

    /**
     * <p>
     * Constructor.
     * </p>
     */
    public StopWatch() {
        super();
    }

    /**
     * <p>
     * Start the stopwatch.
     * </p>
     *
     * <p>
     * This method starts a new timing session, clearing any previous values.
     * </p>
     *
     * @throws IllegalStateException
     *             if the StopWatch is already running.
     */
    public void start() {
        if (this.runningState == State.STOPPED) {
            throw new IllegalStateException("Stopwatch must be reset before being restarted. ");
        }
        if (this.runningState != State.UNSTARTED) {
            throw new IllegalStateException("Stopwatch already started. ");
        }
        this.startTime = System.nanoTime();
        this.startTimeMillis = System.currentTimeMillis();
        this.runningState = State.RUNNING;
    }

    /**
     * <p>
     * Stop the stopwatch.
     * </p>
     *
     * <p>
     * This method ends a new timing session, allowing the time to be retrieved.
     * </p>
     *
     * @throws IllegalStateException
     *             if the StopWatch is not running.
     */
    public void stop() {
        if (this.runningState != State.RUNNING && this.runningState != State.SUSPENDED) {
            throw new IllegalStateException("Stopwatch is not running. ");
        }
        if (this.runningState == State.RUNNING) {
            this.stopTime = System.nanoTime();
        }
        this.runningState = State.STOPPED;
    }

    /**
     * <p>
     * Resets the stopwatch. Stops it if need be.
     * </p>
     *
     * <p>
     * This method clears the internal values to allow the object to be reused.
     * </p>
     */
    public void reset() {
        this.runningState = State.UNSTARTED;
        this.splitState = SplitState.UNSPLIT;
    }

    /**
     * <p>
     * Split the time.
     * </p>
     *
     * <p>
     * This method sets the stop time of the watch to allow a time to be extracted. The start time is unaffected,
     * enabling {@link #unsplit()} to continue the timing from the original start point.
     * </p>
     *
     * @throws IllegalStateException
     *             if the StopWatch is not running.
     */
    public void split() {
        if (this.runningState != State.RUNNING) {
            throw new IllegalStateException("Stopwatch is not running. ");
        }
        this.stopTime = System.nanoTime();
        this.splitState = SplitState.SPLIT;
    }

    /**
     * <p>
     * Remove a split.
     * </p>
     *
     * <p>
     * This method clears the stop time. The start time is unaffected, enabling timing from the original start point to
     * continue.
     * </p>
     *
     * @throws IllegalStateException
     *             if the StopWatch has not been split.
     */
    public void unsplit() {
        if (this.splitState != SplitState.SPLIT) {
            throw new IllegalStateException("Stopwatch has not been split. ");
        }
        this.splitState = SplitState.UNSPLIT;
    }

    /**
     * <p>
     * Suspend the stopwatch for later resumption.
     * </p>
     *
     * <p>
     * This method suspends the watch until it is resumed. The watch will not include time between the suspend and
     * resume calls in the total time.
     * </p>
     *
     * @throws IllegalStateException
     *             if the StopWatch is not currently running.
     */
    public void suspend() {
        if (this.runningState != State.RUNNING) {
            throw new IllegalStateException("Stopwatch must be running to suspend. ");
        }
        this.stopTime = System.nanoTime();
        this.runningState = State.SUSPENDED;
    }

    /**
     * <p>
     * Resume the stopwatch after a suspend.
     * </p>
     *
     * <p>
     * This method resumes the watch after it was suspended. The watch will not include time between the suspend and
     * resume calls in the total time.
     * </p>
     *
     * @throws IllegalStateException
     *             if the StopWatch has not been suspended.
     */
    public void resume() {
        if (this.runningState != State.SUSPENDED) {
            throw new IllegalStateException("Stopwatch must be suspended to resume. ");
        }
        this.startTime += System.nanoTime() - this.stopTime;
        this.runningState = State.RUNNING;
    }

    /**
     * <p>
     * Get the time on the stopwatch.
     * </p>
     *
     * <p>
     * This is either the time between the start and the moment this method is called, or the amount of time between
     * start and stop.
     * </p>
     *
     * @return the time in milliseconds
     */
    public long getTime() {
        return getNanoTime() / NANO_2_MILLIS;
    }

    /**
     * <p>
     * Get the time on the stopwatch in the specified TimeUnit.
     * </p>
     *
     * <p>
     * This is either the time between the start and the moment this method is called, or the amount of time between
     * start and stop. The resulting time will be expressed in the desired TimeUnit with any remainder rounded down.
     * For example, if the specified unit is {@code TimeUnit.HOURS} and the stopwatch time is 59 minutes, then the
     * result returned will be {@code 0}.
     * </p>
     *
     * @param timeUnit the unit of time, not null
     * @return the time in the specified TimeUnit, rounded down
     * @since 3.5
     */
    public long getTime(final TimeUnit timeUnit) {
        return timeUnit.convert(getNanoTime(), TimeUnit.NANOSECONDS);
    }

    /**
     * <p>
     * Get the time on the stopwatch in nanoseconds.
     * </p>
     *
     * <p>
     * This is either the time between the start and the moment this method is called, or the amount of time between
     * start and stop.
     * </p>
     *
     * @return the time in nanoseconds
     * @since 3.0
     */
    public long getNanoTime() {
        if (this.runningState == State.STOPPED || this.runningState == State.SUSPENDED) {
            return this.stopTime - this.startTime;
        } else if (this.runningState == State.UNSTARTED) {
            return 0;
        } else if (this.runningState == State.RUNNING) {
            return System.nanoTime() - this.startTime;
        }
        throw new RuntimeException("Illegal running state has occurred.");
    }

    /**
     * <p>
     * Get the split time on the stopwatch.
     * </p>
     *
     * <p>
     * This is the time between start and latest split.
     * </p>
     *
     * @return the split time in milliseconds
     *
     * @throws IllegalStateException
     *             if the StopWatch has not yet been split.
     * @since 2.1
     */
    public long getSplitTime() {
        return getSplitNanoTime() / NANO_2_MILLIS;
    }
    /**
     * <p>
     * Get the split time on the stopwatch in nanoseconds.
     * </p>
     *
     * <p>
     * This is the time between start and latest split.
     * </p>
     *
     * @return the split time in nanoseconds
     *
     * @throws IllegalStateException
     *             if the StopWatch has not yet been split.
     * @since 3.0
     */
    public long getSplitNanoTime() {
        if (this.splitState != SplitState.SPLIT) {
            throw new IllegalStateException("Stopwatch must be split to get the split time. ");
        }
        return this.stopTime - this.startTime;
    }

    /**
     * Returns the time this stopwatch was started.
     *
     * @return the time this stopwatch was started
     * @throws IllegalStateException
     *             if this StopWatch has not been started
     * @since 2.4
     */
    public long getStartTime() {
        if (this.runningState == State.UNSTARTED) {
            throw new IllegalStateException("Stopwatch has not been started");
        }
        // System.nanoTime is for elapsed time
        return this.startTimeMillis;
    }

    /**
     * <p>
     * Gets a summary of the time that the stopwatch recorded as a string.
     * </p>
     *
     * <p>
     * The format used is ISO 8601-like, <i>hours</i>:<i>minutes</i>:<i>seconds</i>.<i>milliseconds</i>.
     * </p>
     *
     * @return the time as a String
     */
    @Override
    public String toString() {
        return DurationFormatUtils.formatDurationHMS(getTime());
    }

    /**
     * <p>
     * Gets a summary of the split time that the stopwatch recorded as a string.
     * </p>
     *
     * <p>
     * The format used is ISO 8601-like, <i>hours</i>:<i>minutes</i>:<i>seconds</i>.<i>milliseconds</i>.
     * </p>
     *
     * @return the split time as a String
     * @since 2.1
     */
    public String toSplitString() {
        return DurationFormatUtils.formatDurationHMS(getSplitTime());
    }

    /**
     * <p>
     * The method is used to find out if the StopWatch is started. A suspended
     * StopWatch is also started watch.
     * </p>
     *
     * @return boolean
     *             If the StopWatch is started.
     * @since 3.2
     */
    public boolean isStarted() {
        return runningState.isStarted();
    }

    /**
     * <p>
     * This method is used to find out whether the StopWatch is suspended.
     * </p>
     *
     * @return boolean
     *             If the StopWatch is suspended.
     * @since 3.2
     */
    public boolean isSuspended() {
        return runningState.isSuspended();
    }

    /**
     * <p>
     * This method is used to find out whether the StopWatch is stopped. The
     * stopwatch which's not yet started and explicitly stopped stopwatch is
     * considered as stopped.
     * </p>
     *
     * @return boolean
     *             If the StopWatch is stopped.
     * @since 3.2
     */
    public boolean isStopped() {
        return runningState.isStopped();
    }

}

写法三（Scala函数写法）：

import org.slf4j.LoggerFactory

/**
  * 类功能描述：Debug日志追踪
  *
  * @author barry create at 18-8-29 下午3:41
  * @version 1.0.0
  */
object Debug {
  val LOGGER = LoggerFactory.getLogger(getClass)
  val counter = collection.mutable.Map[String, Int]() // label -> count
  val times = collection.mutable.Map[String, Long]() // label - time(ns)

  /**
    *追踪代码块
    * @param label 标签名
    * @param codeBlock 代码块
    * @tparam T 返回结果类型
    * @return
    */
  def trace[T](label: String)(codeBlock: => T) = {
    val t0 = System.nanoTime()
    val result = codeBlock
    val t1 = System.nanoTime()
    counter.get(label).map(_counter => counter.put(label, _counter + 1)).orElse(counter.put(label, 1))
    times.get(label).map(cost => times.put(label, cost + (t1 - t0))).orElse(times.put(label, t1 - t0))
    result
  }

  /**
    * 打印日志
    */
  def info(): Unit = {
    LOGGER.warn("FinallyDone...")
    LOGGER.warn(s"counter:${counter}")
    LOGGER.warn(s"times:${times.map { case (label, cost) => (label, cost / 1000000)}}ms")
  }

  /**
    * 重新计数
    */
  def reset(): Unit = {
    counter.clear()
    times.clear()
  }
}

参考下面测试代码：

java版本：

 /**
  * @author WangXueXing create at 19-7-31 下午1:46
  * @version 1.0.0
  */
 public class StopWatchDemo {
     public static void main(String[] args){
         Debug.trace("方法1调用次数及用时", ()->{
             try {
                 Thread.sleep(2000);
             } catch (InterruptedException e) {
                 e.printStackTrace();
             }
             return "";
         });

         Debug.trace("方法1调用次数及用时", ()->{
             try {
                 Thread.sleep(2000);
             } catch (InterruptedException e) {
                 e.printStackTrace();
             }
             return "";
         });

         Debug.trace("方法2调用次数及用时", ()->{
             try {
                 Thread.sleep(2000);
             } catch (InterruptedException e) {
                 e.printStackTrace();
             }
             return 10;
         });

         Debug.info();
     }
 }

输出结果：

15:29:32.228 [main] WARN  test.Debug$ - FinallyDone...
15:29:32.361 [main] WARN  test.Debug$ - counter:Map(方法2调用次数及用时 -> 1, 方法1调用次数及用时 -> 2)
15:29:32.364 [main] WARN  test.Debug$ - times:Map(方法2调用次数及用时 -> 2000, 方法1调用次数及用时 -> 4000)ms

　　

scala版本：

/**
  * @author WangXueXing create at 19-8-1 下午3:40
  * @version 1.0.0
  */
object StopWatchTest {
  def main(args: Array[String]): Unit = {
    Debug.trace("方法1调用次数及用时")( Thread.sleep(200))
    Debug.trace("方法1调用次数及用时")( Thread.sleep(200))
    Debug.trace("方法2调用次数及用时")( Thread.sleep(200))
    Debug.info()
  }
}

输出结果：

15:43:58.601 [main] WARN  test.stopwatch.Debug$ - FinallyDone...
15:43:58.735 [main] WARN  test.stopwatch.Debug$ - counter:Map(方法2调用次数及用时 -> 1, 方法1调用次数及用时 -> 2)
15:43:58.739 [main] WARN  test.stopwatch.Debug$ - times:Map(方法2调用次数及用时 -> 200, 方法1调用次数及用时 -> 400)ms

　　

对比java版本与scala版本，是不是看到scala的简洁及强大了吧！