Quartz

Quartz 是一個功能滿完整的 Java Schedule 排程工具, 核心就圍繞在 Scheduler 與 Job 的操作上。

• Scheduler - the main API for interacting with the scheduler.
• Job - an interface to be implemented by components that you wish to have executed by the scheduler.
• JobDetail - used to define instances of Jobs.
• Trigger - a component that defines the schedule upon which a given Job will be executed.
• JobBuilder - used to define/build JobDetail instances, which define instances of Jobs.
• TriggerBuilder - used to define/build Trigger instances.

Job

Quartz 的 Job 被定義為需要 implement org.quartz.Job,
需要實作 void execute(JobExecutionContext jobExecutionContext),
jobExecutionContext, 可以取得 Job 的 Scheduler, Trigger, JobDetail 的相關設定, 相關的說明可以參考 tutorial-lesson-02.

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.quartz.Job;
import org.quartz.JobDataMap;
import org.quartz.JobDetail;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;

/**
 * Created by jerry on 2017/11/17.
 */
public class HelloJob implements Job {

    /**
     * Quartz Job 要求要一個 empty constructor,
     * 讓 Scheduler 來 instantiate
     */
    public HelloJob() {
    }

    /**
     * Quartz Job 要執行的動作
     *
     * @param jobExecutionContext
     * @throws JobExecutionException
     */
    @Override
    public void execute(JobExecutionContext jobExecutionContext) throws JobExecutionException {
        ObjectMapper objectMapper = new ObjectMapper();
        JobDetail jobInstant = jobExecutionContext.getJobDetail();
        System.out.println("===========================================");
        System.out.println("Description: " + jobInstant.getDescription());
        System.out.println("Job Key: " + jobInstant.getKey());
        System.out.println("is Concurrent Execution Disallowed: " + jobInstant.isConcurrentExectionDisallowed());
        System.out.println("is Durable: " + jobInstant.isDurable());
        System.out.println("requests Recovery: " + jobInstant.requestsRecovery());

        System.out.println("===========================================");
        JobDataMap jobData = jobInstant.getJobDataMap();

        try {
            String jobDataJson = objectMapper.writeValueAsString(jobData);
            System.out.println("Job Data Map Data: " + jobDataJson);

        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }

    }
}

Scheduler

定義完 Job 之後, 要觸發還需要 Scheduler, Scheduler 可以用來分配 Job 與 Trigger,
藉由 SchedulerFactory 來取得 instance, SchedulerFactory 會載入 quartz.properties 定義的相關設定（參考）

import static org.quartz.DateBuilder.evenMinuteDate;
import static org.quartz.JobBuilder.newJob;
import static org.quartz.TriggerBuilder.newTrigger;

import com.google.common.collect.ImmutableMap;
import org.quartz.JobDataMap;
import org.quartz.JobDetail;
import org.quartz.Scheduler;
import org.quartz.SchedulerException;
import org.quartz.SchedulerFactory;
import org.quartz.Trigger;
import org.quartz.impl.StdSchedulerFactory;

import java.util.Date;

/**
 * Created by jerry on 2017/11/17.
 */
public class HelloWorldSchedule {
    
    public void run() throws SchedulerException, InterruptedException {
        // init job
        JobDetail job = newJob(HelloJob.class)
            .withDescription("quartz job - hello world")
            .withIdentity("job-name", "job-group")
            .usingJobData("string-key", "value1")
            .usingJobData("long-key", 1L)
            .usingJobData(new JobDataMap(
                ImmutableMap.builder().put("map-key", "map-value").build()))
            .build();

        // set trigger time
        Date runTime = evenMinuteDate(new Date());

        // init trigger, start at next even minute time
        Trigger trigger = newTrigger()
            .withIdentity("trigger-name", "trigger-group")
            .startAt(runTime)
            .build();

        // init schedule
        SchedulerFactory schedulerFactory = new StdSchedulerFactory();
        Scheduler scheduler = schedulerFactory.getScheduler();
        scheduler.scheduleJob(job, trigger);

        // start up schedule
        scheduler.start();

        // sleep 10 seconds, make sure the scheduler be triggered
        Thread.sleep(60L * 1000);

        scheduler.shutdown(true);
    }
}

Run Scheduler

@Test
public void testScheduler() throws SchedulerException, InterruptedException {
    HelloWorldSchedule helloWorldSchedule = new HelloWorldSchedule();
    helloWorldSchedule.run();
}