定时任务 quartz

Quartz有四个核心接口Job、JobDetail、Trigger和Scheduler。Trigger主要有CronTrigger（表达式触发）和SimpleTrigger（简单触发）两个接口，表达式触发的功能更强大，在开发时使用比较广泛，Job是一个实现org.quartz.Job接口的java类。将需要完成的任务写在execute（）方法中。一个job可以有多个trigger，一个trigger只能有一个job。JobDetail包含了Job的调度策略和调度方案。Scheduler是对定时任务进行调度的控制器。Quartz的运行原理如图所示。

Scheduler是整个任务调度的总部，里面注册了很多的JobDetail和trigger。Trigger主要用来设置调度参数，用来设置多久进行一次任务调度。当Scheduler容器启动时，JobDetail和Trigger会在scheduler容器上进行注册。注册后，JobDetail和Trigger将会组成的一对装配好的作业。在Scheduler中有一个线程池，按照Trigger中配置的规则，为每个作业开启一个线程来并行执行。 

SimpleTrigger

应用小demo

public class HelloJob implements Job{
    public void execute(JobExecutionContext jobExecutionContext) throws JobExecutionException {
        System.out.println(new Date());
    }
}
=================================================================

package job;

import org.quartz.JobDetail;
import org.quartz.Scheduler;
import org.quartz.SchedulerFactory;
import org.quartz.Trigger;
import org.quartz.impl.StdSchedulerFactory;
import java.util.Date;
import static org.quartz.DateBuilder.evenSecondDate;
import static org.quartz.JobBuilder.newJob;
import static org.quartz.TriggerBuilder.newTrigger;

/**
 * created by reedfan on 2019/7/4 0004
 */
public class SimpleExample {
    public void run() throws Exception {
        System.out.println("------- Initializing ----------------------");
        // 定义调度器
        SchedulerFactory sf = new StdSchedulerFactory();
        Scheduler sched = sf.getScheduler();
        System.out.println("------- Initialization Complete -----------");
        // 获取当前时间的下一秒钟
        Date runTime = evenSecondDate(new Date());
        System.out.println("------- Scheduling Job  -------------------");
        // 定义job
        // 在quartz中，有组的概念，组+job名称 唯一的
        JobDetail job = newJob(HelloJob.class).withIdentity("job1", "group1").build();
        // 定义触发器，在下一秒钟启动
        Trigger trigger = newTrigger().withIdentity("trigger1", "group1").startAt(runTime).build();
        // 将job注册到调度器
        sched.scheduleJob(job, trigger);
        System.out.println(job.getKey() + " will run at: " + runTime);
        // 启动调度器
        sched.start();
        System.out.println("------- Started Scheduler -----------------");
        // 等待5秒
        System.out.println("------- Waiting 5 seconds... -------------");
        try {
            // wait 65 seconds to show job
            Thread.sleep(5L * 1000L);
            // executing...
        } catch (Exception e) {
            //
        }
        // 关闭调度器
        System.out.println("------- Shutting Down ---------------------");
        sched.shutdown(true);
        System.out.println("------- Shutdown Complete -----------------");
    }

    public static void main(String[] args) throws Exception {
        SimpleExample example = new SimpleExample();
        example.run();

    }
}

运行结果

CronTrigger

quartz表达式生成器

package job;

import org.quartz.JobDetail;
import org.quartz.Scheduler;
import org.quartz.SchedulerFactory;
import org.quartz.Trigger;
import org.quartz.impl.StdSchedulerFactory;
import java.util.Date;

import static org.quartz.CronScheduleBuilder.cronSchedule;
import static org.quartz.DateBuilder.evenSecondDate;
import static org.quartz.JobBuilder.newJob;
import static org.quartz.TriggerBuilder.newTrigger;

/**
 * created by reedfan on 2019/7/4 0004
 */
public class SimpleExample {
    public void run() throws Exception {
        System.out.println("------- Initializing ----------------------");
        // 定义调度器
        SchedulerFactory sf = new StdSchedulerFactory();
        Scheduler sched = sf.getScheduler();
        System.out.println("------- Initialization Complete -----------");
        // 获取当前时间的下一秒钟
        Date runTime = evenSecondDate(new Date());
        System.out.println("------- Scheduling Job  -------------------");
        // 定义job
        // 在quartz中，有组的概念，组+job名称 唯一的
        JobDetail job = newJob(HelloJob.class).withIdentity("job1", "group1").build();
        // 定义触发器，在下一钟启动
      //  Trigger trigger = newTrigger().withIdentity("trigger1", "group1").startAt(runTime).build();
        // 将job注册到调度器

        // 定义触发器，每2秒执行一次
        Trigger trigger = newTrigger().withIdentity("trigger1", "group1")
                .withSchedule(cronSchedule("0/2 * * * * ?")).build();

        sched.scheduleJob(job, trigger);
        System.out.println(job.getKey() + " will run at: " + runTime);
        // 启动调度器
        sched.start();
        System.out.println("------- Started Scheduler -----------------");
        // 等待5秒
        System.out.println("------- Waiting 10 seconds... -------------");
        try {
            // wait 10 seconds to show job
            Thread.sleep(10L * 1000L);
            // executing...
        } catch (Exception e) {
            //
        }
        // 关闭调度器
        System.out.println("------- Shutting Down ---------------------");
        sched.shutdown(true);
        System.out.println("------- Shutdown Complete -----------------");
    }

    public static void main(String[] args) throws Exception {
        SimpleExample example = new SimpleExample();
        example.run();

    }
}