如何在java中的石英调度中将数组作为参数传递

Question

I want to pass a string array to the class which is being scheduled and called by the Scheduler object. The scheduler class is as follows :

 String stuff[]={"",""}
 JobDetail job = JobBuilder.newJob(HelloJob.class)
                 .withIdentity("job", "group1").build();
 job.getJobDataMap().put(HelloJob.data, stuff);

Trigger trigger = TriggerBuilder
                   .newTrigger()
                   .withSchedule(
                    CronScheduleBuilder.cronSchedule(time))
                   .build();
    //schedule it
Scheduler scheduler = new StdSchedulerFactory().getScheduler();
System.out.println("Before starting");
scheduler.start();
scheduler.scheduleJob(job, trigger);

passing the array to :

public class HelloJob implements Job {
    static String data[];
    public void execute(JobExecutionContext context) throws JobExecutionException {
        System.out.println("Job");  
    }
}

the job interface :

     public interface Job {
             void execute(JobExecutionContext context)
              throws JobExecutionException;
      }

Is there any solution to pass the array?

Answer 1

Yes, there is a solution.

1. Delete static String data[] in HelloJob . Avoid static (particularly arrays) as much as possible.

2. When you call put on the JobDataMap you need to provide a key and a value. The value is your array, but you need to pick a key. As it was, you were using the static String.data array reference which, in your code, was always null (not a good idea). You need to define a suitable, well-known key. There are a number of options available to you, but a simple solution is...

3. Add static final String DATA_ARRAY_KEY = "data_array"; to HelloJob . Despite what I said in #1 about avoiding statics, this one is safe because it's final and, unlike an array, a String cannot ever be modified. We're using this as a constant , your well-known key. Now your put() call should look like: put(HelloJob.DATA_ARRAY_KEY, stuff)

4. Now you need to get the array out when the Job runs its execute method. In that method, you can access your JobDataMap by calling context.getMergedJobDataMap() and from that you can get(DATA_ARRAY_KEY) and cast the result back to String[] .

That should solve your original question. However, you didn't give an example of what was going to be in your array. Depending on how you intended to use it, it might be a better solution to use the specialized methods on JobDataMap like putAsString(String key, String value) and getAsString(String key) .