以编程方式创建动态石英调度程序

Created: November-22, 2018

我们可能需要创建一个 Quartz 调度程序，根据用户输入何时应该触发调度程序，除了我们可以处理的情况，我们有一些预先定义的功能，需要根据用户操作，在某个时间段。

此示例接收有关触发定时的用户输入，以触发调度程序。这是 ScheduledJobListener 类 imlements MessageListener，其中包含在触发调度程序时要执行的业务逻辑。在配置所需的参数后，使用 SchedulerEngineHelperUtilclass 调度作业以触发作业：

触发（使用 cron 文本字符串和作业名称）
消息（使用 MessageListener 类和 portletId 的实现）
调度程序存储类型（默认情况下为 MEMORY_CLUSTERED，可以设置为 PERSISTED 以存储在 DB 中）
DestinationNames（Liferay 的 SCHEDULER_DISPATCH）决定要使用的消息总线目标

下面的代码片段是 portlet 与用户交互的动作阶段的一部分，用于创建和安排石英作业。

   //Dynamic scheduling
    String portletId= (String)req.getAttribute(WebKeys.PORTLET_ID);
                  
    String jobName= ScheduledJobListener.class.getName();
           
    Calendar startCalendar = new GregorianCalendar(year , month, day, hh, mm, ss);
    String jobCronPattern = SchedulerEngineHelperUtil.getCronText(startCalendar, false);
                                //Calendar object & flag for time zone sensitive calendar
    
    Trigger trigger=new CronTrigger(ScheduledJobListener.class.getName(),ScheduledJobListener.class.getName(), jobCronPattern);
            
    Message message=new Message();
    message.put(SchedulerEngine.MESSAGE_LISTENER_CLASS_NAME,jobName);
    message.put(SchedulerEngine.PORTLET_ID, portletId);
    
    try {
          SchedulerEngineHelperUtil.schedule(
                trigger,StorageType.PERSISTED,"Message_Desc",DestinationNames.SCHEDULER_DISPATCH,
                message,0);                    
         } catch (SchedulerException e) 
                {
                    e.printStackTrace();
                }

这里，为了创建 cron 文本，从用户输入检索 params 对于 cron 文本，我们也可以使用给定的引用来创建 cron 模式

    1. Seconds
    2. Minutes
    3. Hours
    4. Day-of-Month
    5. Month
    6. Day-of-Week
    7. Year (optional field)
    **Expression**     **Meaning**
    0 0 12 * * ?     Fire at 12pm (noon) every day
    0 15 10 ? * *     Fire at 10:15am every day
    0 15 10 * * ?     Fire at 10:15am every day
    0 15 10 * * ? *     Fire at 10:15am every day
    0 15 10 * * ? 2005     Fire at 10:15am every day during the year 2005
    0 * 14 * * ?     Fire every minute starting at 2pm and ending at 2:59pm, every day
    0 0/5 14 * * ?     Fire every 5 minutes starting at 2pm and ending at 2:55pm, every day
    0 0/5 14,18 * * ?     Fire every 5 minutes starting at 2pm and ending at 2:55pm, AND fire every 5 minutes starting at 6pm and ending at 6:55pm, every day
    0 0-5 14 * * ?     Fire every minute starting at 2pm and ending at 2:05pm, every day
    0 10,44 14 ? 3 WED     Fire at 2:10pm and at 2:44pm every Wednesday in the month of March.
    0 15 10 ? * MON-FRI     Fire at 10:15am every Monday, Tuesday, Wednesday, Thursday and Friday
    0 15 10 15 * ?     Fire at 10:15am on the 15th day of every month
    0 15 10 L * ?     Fire at 10:15am on the last day of every month
    0 15 10 L-2 * ?     Fire at 10:15am on the 2nd-to-last last day of every month
    0 15 10 ? * 6L     Fire at 10:15am on the last Friday of every month
    0 15 10 ? * 6L     Fire at 10:15am on the last Friday of every month
    0 15 10 ? * 6L 2002-2005     Fire at 10:15am on every last friday of every month during the years 2002, 2003, 2004 and 2005
    0 15 10 ? * 6#3     Fire at 10:15am on the third Friday of every month
    0 0 12 1/5 * ?     Fire at 12pm (noon) every 5 days every month, starting on the first day of the month.
    0 11 11 11 11 ?     Fire every November 11th at 11:11am.

并根据用户输入直接创建要使用的 crontext 字符串

 String jobCronPattern="0 */5 * * * ?";

在这种情况下，它每隔五分钟就会发射一次。

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