java - 如何更新 Quartz JobDataMap 中的值？

Question

我正在使用 quartz-scheduler 1.8.5。我创建了一个实现 StatefulJob 的工作。我使用 SimpleTrigger 和 StdSchedulerFactory 安排作业。

除了 JobDetail 的 JobDataMap 之外，我似乎还必须更新 Trigger 的 JobDataMap 才能从作业内部更改 JobDataMap。我想了解为什么有必要同时更新两者？我注意到 JobDataMap 设置为脏。也许我必须明确保存它或其他什么？

我想我必须深入研究 Quartz 的源代码才能真正理解这里发生了什么，但我想我会偷懒，先问问。感谢您深入了解 JobDataMap 的内部工作原理!

这是我的工作:

public class HelloJob implements StatefulJob {

    public HelloJob() {
    }

    public void execute(JobExecutionContext context)
            throws JobExecutionException {

        int count = context.getMergedJobDataMap().getInt("count");
        int count2 = context.getJobDetail().getJobDataMap().getInt("count");
        //int count3 = context.getTrigger().getJobDataMap().getInt("count");
        System.err.println("HelloJob is executing. Count: '"+count+"', "+count2+"'");

        //The count only gets updated if I updated both the Trigger and 
                // JobDetail DataMaps. If I only update the JobDetail, it doesn't persist. 
        context.getTrigger().getJobDataMap().put("count", count++);
        context.getJobDetail().getJobDataMap().put("count", count++);

        //This has no effect inside the job, but it works outside the job
        try {
            context.getScheduler().addJob(context.getJobDetail(), true);
        } catch (SchedulerException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        //These don't seem to persist between jobs
        //context.put("count", count++);
        //context.getMergedJobDataMap().put("count", count++);
    }
}

这是我安排工作的方式:

try {
    // define the job and tie it to our HelloJob class
    JobDetail job = new JobDetail(JOB_NAME, JOB_GROUP_NAME,
            HelloJob.class);
    job.getJobDataMap().put("count", 1);
    // Trigger the job to run now, and every so often
    Trigger trigger = new SimpleTrigger("myTrigger", "group1",
            SimpleTrigger.REPEAT_INDEFINITELY, howOften);

    // Tell quartz to schedule the job using our trigger
    sched.scheduleJob(job, trigger);
    return job;
} catch (SchedulerException e) {
    throw e;
}

更新:

似乎我必须将值放入 JobDetail 的 JobDataMap 两次才能让它持久化，这是可行的:

public class HelloJob implements StatefulJob {

    public HelloJob() {
    }

    public void execute(JobExecutionContext context)
            throws JobExecutionException {

        int count = (Integer) context.getMergedJobDataMap().get("count");
        System.err.println("HelloJob is executing. Count: '"+count+"', and is the job stateful? "+context.getJobDetail().isStateful());
        context.getJobDetail().getJobDataMap().put("count", count++);
        context.getJobDetail().getJobDataMap().put("count", count++);
    }
}

这似乎是一个错误，也许吧？或者我可能缺少一个步骤来告诉 JobDetail 将其 JobDataMap 的内容刷新到 JobStore？

Answer 1

我认为您的问题在于使用后缀++ 运算符 - 当您这样做时:

context.getJobDetail().getJobDataMap().put("count", count++);  

您正在将 map 中的值设置为计数，然后递增计数。

在我看来你想要的是:

context.getJobDetail().getJobDataMap().put("count", ++count);  

这只需要做一次。