Quartz任务执行

    quartz任务调度器,有个很忧伤的限制,就是提交的任务只能指定Job class类型,具体job的实例实例化有quartz来创建,且任务每次执行都会创建一个job实例,在某些场景下,我们可能需要传递一个job实例(比如job的属性有其他方式注入),那么直接使用quartz则不太能满足,我们需要借助dataMap来传递自己的实例.例如:

 

CronScheduleBuilder sb = CronScheduleBuilder.cronSchedule(cronExpression);
Trigger trigger = TriggerBuilder.newTrigger().withIdentity(key, GROUP).withSchedule(sb).build();
//如果任务已经在执行,则返回
if(scheduler.checkExists(trigger.getKey())){
	return true;
}
Class<MyJob> jobClass = MyJob.class;
JobDetail job = JobBuilder.newJob(jobClass).withIdentity(key, GROUP).build();
scheduler.scheduleJob(job, trigger);

    其中MyJob就是我们自己的Job类,他实现了Job接口..接下来我们使用一种变通的方式来使用quartz.:

 

 

1. JobExecutor接口: 所有的可执行任务,都需要实现这个接口 .

 

public interface JobExecutor {

    public void execute();
}

 

 

2. JobProxy类:当任务调度时,充当代理层,间接的执行JobExecutor实例方法.

 

public class JobProxy implements Job {

private static Logger log = Logger.getLogger(JobProxy.class);

	@Override
	public void execute(JobExecutionContext context) throws JobExecutionException {
		
		JobExecutor executor = (JobExecutor)context.getJobDetail().getJobDataMap().get(Utils.WORKER_CALLER);
		if(executor == null){
			return;
		}
		
		try{
			executor.execute();//调用自定义的JobExecutor实例,此实例通过dataMap传递
		}catch(Exception e){
			e.printStackTrace();
		}

	}
}

 

 

3. JobScheduler类:任务的调度与取消

 

public class JobScheduler {

    private Scheduler scheduler;

    private static final String GROUP = "_default-group_";
    public JobScheduler() throws Exception{
        scheduler = StdSchedulerFactory.getDefaultScheduler();
        scheduler.start();
    }

    public boolean schedule(String key,String cronExpression,JobExecutor executor){
        try {
            CronScheduleBuilder sb = CronScheduleBuilder.cronSchedule(cronExpression);
            Trigger trigger = TriggerBuilder.newTrigger().withIdentity(key, GROUP).withSchedule(sb).build();
            //如果任务已经在执行,则返回
            if(scheduler.checkExists(trigger.getKey())){
                return true;
            }
            Class<JobProxy> jobClass = JobProxy.class;
            JobDetail job = JobBuilder.newJob(jobClass).withIdentity(key, GROUP).build();
            job.getJobDataMap().put(Utils.WORKER_ID, key); //for get
            job.getJobDataMap().put(Utils.WORKER_CALLER, executor);   //for get
            scheduler.scheduleJob(job, trigger);
            // 任务调度列表
            return true;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }


    public boolean unschedule(String key){
        try {
            TriggerKey tk = new TriggerKey(key, GROUP);
            if (scheduler.checkExists(tk)) {
                scheduler.unscheduleJob(tk);
            }
            return true;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }
}

    并没有特别神秘的地方,只是借助了dataMap来保存JobDeTetail的实例.