java 如何获得给定作业名称和组名称的 cron 表达式？
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How to get cron expression given job name and group name?
提问by Gnanam
I'm using Quartz Scheduler v.1.8.0.
我正在使用 Quartz Scheduler v.1.8.0。
How do I get the cron expression which was assigned/attached to a Job and scheduled using CronTrigger? I have the job name and group name in this case. Though many Triggers can point to the same Job, in my case it is only one.
如何获取分配/附加到作业并使用CronTrigger调度的 cron 表达式？在这种情况下，我有作业名称和组名称。尽管许多触发器可以指向同一个 Job，但在我的情况下它只有一个。
There is a method available in Scheduler class, Scheduler.getTriggersOfJob(jobName, groupName), but it returns only Triggerarray.
Scheduler 类中有一个可用的方法，Scheduler.getTriggersOfJob(jobName, groupName)，但它只返回Trigger数组。
Example cronexpression: 0 /5 10-20 * * ?
示例 cron 表达式： 0 /5 10-20 * * ?
NOTE:Class CronTriggerextends Trigger
注意：CronTrigger类扩展了触发器
回答by Vivien Barousse
You can use Scheduler.getTriggerOfJob. This class returns all triggers for a given jobName and groupName, in a Trigger[].
您可以使用 Scheduler.getTriggerOfJob。此类在 Trigger[] 中返回给定 jobName 和 groupName 的所有触发器。
Then, analyse the content of this array, test if the Trigger is a CronTrigger, and cast it to get the CronTrigger instance. Then, the getCronExpression() method should return what you are looking for.
然后，分析这个数组的内容，测试Trigger是否是CronTrigger，并强制转换得到CronTrigger实例。然后， getCronExpression() 方法应该返回您要查找的内容。
Here is a code sample:
这是一个代码示例：
Trigger[] triggers = // ... (getTriggersOfJob)
for (Trigger trigger : triggers) {
if (trigger instanceof CronTrigger) {
CronTrigger cronTrigger = (CronTrigger) trigger;
String cronExpr = cronTrigger.getCronExpression();
}
}
