计算任务执行时间-SpringBoot - StopWatch

SpringBoot 启动过程中使用到了StopWatch 对象,被称为秒表对象。这个对象针对任务提供了任务执行时间总任务时间方法

优点

增加了代码可读性,隐藏了System.nanoTime()实现细节。降低了代码出错率

简单使用方法

public static void main(String[] args) throws InterruptedException {
        // 创建秒表对象
        StopWatch stopWatch = new StopWatch("对象ID-标识");
        // 启动秒表
        stopWatch.start("任务名称");
        // 模拟业务运行时间-停留两秒
        TimeUnit.SECONDS.sleep(2);
        // 停止秒表
        stopWatch.stop();
        /**
         * 获取最后一个任务毫秒
         */
        System.out.println(stopWatch.getLastTaskTimeMillis());
        /**
         * 获取最后一个任务秒
         */
        System.out.println(stopWatch.getLastTaskInfo().getTimeSeconds());
        /**
         * 获取最后一个任务纳秒
         */
        System.out.println(stopWatch.getLastTaskInfo().getTimeNanos());
        /**
         * 获取任务数组
         */
        System.out.println(stopWatch.getTaskInfo());
    }

时间格式化

  1. 转换方法

public static String msTime2Duration(long msDuration) {
        //使用lang3工具类
        String durationStr = DurationFormatUtils.formatDuration(msDuration, "d'天'H'时'm'分's'秒'");
        durationStr = durationStr.replace("0天0时0分", "");
        durationStr = durationStr.replace("0天0时", "");
        durationStr = durationStr.replace("0天", "");
        return durationStr;
    }
  1. 如果缺少JAR包


    org.apache.commons
    commons-lang3

StopWatch对象源码解析

public class StopWatch {

    // ID标识符
    private final String id;
    // 是否流程留存任务历史
    private boolean keepTaskList = true;
    // 任务集合如果keepTaskList为true,每次任务都会添加
    private final List taskList = new LinkedList<>();

    /** 任务开始时间 */
    private long startTimeNanos;

    /** 任务名称 */
    @Nullable
    private String currentTaskName;
    
    // 最后一次执行的任务
    @Nullable
    private TaskInfo lastTaskInfo;
    
    // 任务总数
    private int taskCount;

    /** 所有任务运行总时长 */
    private long totalTimeNanos;


    /**
     * 无参构造器,秒表的ID为空字符串
     */
    public StopWatch() {
        this("");
    }

    /**
     * 自定义ID
     */
    public StopWatch(String id) {
        this.id = id;
    }


    /**
     * 获取ID
     */
    public String getId() {
        return this.id;
    }

    /**
     * 设置流程留存标识
     */
    public void setKeepTaskList(boolean keepTaskList) {
        this.keepTaskList = keepTaskList;
    }


    /**
     * 开始秒表。任务名称为空字符串
     */
    public void start() throws IllegalStateException {
        start("");
    }

    /**
     * 开始秒表,自定义任务名称
     */
    public void start(String taskName) throws IllegalStateException {
        if (this.currentTaskName != null) {
            throw new IllegalStateException("Can't start StopWatch: it's already running");
        }
        this.currentTaskName = taskName;
        this.startTimeNanos = System.nanoTime();
    }

    /**
     * 停止秒表
     */
    public void stop() throws IllegalStateException {
        if (this.currentTaskName == null) {
            throw new IllegalStateException("Can't stop StopWatch: it's not running");
        }
        long lastTime = System.nanoTime() - this.startTimeNanos;
        this.totalTimeNanos += lastTime;
        this.lastTaskInfo = new TaskInfo(this.currentTaskName, lastTime);
        if (this.keepTaskList) {
            this.taskList.add(this.lastTaskInfo);
        }
        ++this.taskCount;
        this.currentTaskName = null;
    }

    /**
     * 判断是否正在运行
     */
    public boolean isRunning() {
        return (this.currentTaskName != null);
    }

    /**
     * 获取当前任务名称
     */
    @Nullable
    public String currentTaskName() {
        return this.currentTaskName;
    }

    /**
     * 获取最后一个任务的纳秒时间
     */
    public long getLastTaskTimeNanos() throws IllegalStateException {
        if (this.lastTaskInfo == null) {
            throw new IllegalStateException("No tasks run: can't get last task interval");
        }
        return this.lastTaskInfo.getTimeNanos();
    }

    /**
     * 获取最后一个任务的毫秒
     */
    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();
    }

    /**
     * 获取最后一个任务的任务名称
     */
    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();
    }

    /**
     * 获取最后一个任务的信息
     */
    public TaskInfo getLastTaskInfo() throws IllegalStateException {
        if (this.lastTaskInfo == null) {
            throw new IllegalStateException("No tasks run: can't get last task info");
        }
        return this.lastTaskInfo;
    }


    /**
     * 获取所有任务的总时长
     */
    public long getTotalTimeNanos() {
        return this.totalTimeNanos;
    }

    /**
     * 获取总任务时长毫秒
     */
    public long getTotalTimeMillis() {
        return nanosToMillis(this.totalTimeNanos);
    }

    /**
     * 获取总任务市场秒
     */
    public double getTotalTimeSeconds() {
        return nanosToSeconds(this.totalTimeNanos);
    }

    /**
     * 获取总任务数量
     */
    public int getTaskCount() {
        return this.taskCount;
    }

    /**
     * 获取所有任务信息
     */
    public TaskInfo[] getTaskInfo() {
        if (!this.keepTaskList) {
            throw new UnsupportedOperationException("Task info is not being kept!");
        }
        return this.taskList.toArray(new TaskInfo[0]);
    }


    /**
     * 获取当前任务简短信息
     */
    public String shortSummary() {
        return "StopWatch '" + getId() + "': running time = " + getTotalTimeNanos() + " ns";
    }

    /**
     * 打印任务信息
     */
    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("ns         %     Task name\n");
            sb.append("---------------------------------------------\n");
            NumberFormat nf = NumberFormat.getNumberInstance();
            nf.setMinimumIntegerDigits(9);
            nf.setGroupingUsed(false);
            NumberFormat pf = NumberFormat.getPercentInstance();
            pf.setMinimumIntegerDigits(3);
            pf.setGroupingUsed(false);
            for (TaskInfo task : getTaskInfo()) {
                sb.append(nf.format(task.getTimeNanos())).append("  ");
                sb.append(pf.format((double) task.getTimeNanos() / getTotalTimeNanos())).append("  ");
                sb.append(task.getTaskName()).append("\n");
            }
        }
        return sb.toString();
    }


    @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.getTimeNanos()).append(" ns");
                long percent = Math.round(100.0 * task.getTimeNanos() / getTotalTimeNanos());
                sb.append(" = ").append(percent).append("%");
            }
        }
        else {
            sb.append("; no task info kept");
        }
        return sb.toString();
    }


    private static long nanosToMillis(long duration) {
        return TimeUnit.NANOSECONDS.toMillis(duration);
    }

    private static double nanosToSeconds(long duration) {
        return duration / 1_000_000_000.0;
    }


    /**
     * 任务对象信息
     */
    public static final class TaskInfo {

        private final String taskName;

        private final long timeNanos;

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

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

        /**
         * Get the time in nanoseconds this task took.
         * @since 5.2
         * @see #getTimeMillis()
         * @see #getTimeSeconds()
         */
        public long getTimeNanos() {
            return this.timeNanos;
        }

        /**
         * Get the time in milliseconds this task took.
         * @see #getTimeNanos()
         * @see #getTimeSeconds()
         */
        public long getTimeMillis() {
            return nanosToMillis(this.timeNanos);
        }

        /**
         * Get the time in seconds this task took.
         * @see #getTimeMillis()
         * @see #getTimeNanos()
         */
        public double getTimeSeconds() {
            return nanosToSeconds(this.timeNanos);
        }

    }

}

完结

以上就是SpringBoot 中 StopWatch 对象的具体使用方式和源码解释了,如果有哪里说的不对。可以评论探讨

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