带你浅谈下Quartz的简单使用

Scheduler 每次执行，都会根据JobDetail创建一个新的Job实例，这样就可以规避并发访问的问题（jobDetail的实例也是新的）

Quzrtz 定时任务默认都是并发执行，不会等待上一次任务执行完毕，只要间隔时间到就会执行，如果定时任务执行太长，会长时间占用资源，导致其它任务堵塞

@
DisallowConcurrentExecution: job类上，禁止并发地执行同一个job定义 (JobDetail定义的)的多个实例。

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scheduler：可以理解为定时任务的工作容器或者说是工作场所，所有定时任务都是放在里面工作，可以开启和停止。
trigger：可以理解为是定时任务任务的工作规则配置，例如说，没个几分钟调用一次，或者说指定每天那个时间点执行。
jobDetail：定时任务的信息，例如配置定时任务的名字，群组之类的。
job：定时任务的真正的业务处理逻辑的地方。

简单示例

TestClient.Java

import org.quartz.*;
import org.quartz.impl.StdSchedulerFactory;public class TaskClient {public static void main(String[] args) {JobDetail jobDetail = JobBuilder.newJob(TaskJob.class).withIdentity("job1", "group1")  //设置JOB的名字和组.build();Trigger trigger = TriggerBuilder.newTrigger().withIdentity("trigger1", "trigger1").startNow().withSchedule(SimpleScheduleBuilder.simpleSchedule().withIntervalInSeconds(1).repeatForever()).build();try {Scheduler scheduler = StdSchedulerFactory.getDefaultScheduler();scheduler.scheduleJob(jobDetail,trigger);scheduler.start();} catch (SchedulerException ex) {ex.printStackTrace();}}}

TaskJob.Java

import cn.hutool.core.date.DateUtil;
import org.quartz.Job;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;public class TaskJob implements Job {@Overridepublic void execute(JobExecutionContext jobExecutionContext) throws JobExecutionException {System.out.println("TaskJob => " + DateUtil.now());}
}

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usingJobData

通过 usingJobData 往定时任务中传递参数

import org.quartz.*;
import org.quartz.impl.StdSchedulerFactory;public class TaskClient {public static void main(String[] args) {JobDetail jobDetail = JobBuilder.newJob(TaskJob.class).withIdentity("job1", "group1").usingJobData("job","jobDetail1.JobDataMap.Value").build();Trigger trigger = TriggerBuilder.newTrigger().withIdentity("trigger1", "trigger1").usingJobData("trigger","trigger.JobDataMap.Value").startNow().withSchedule(SimpleScheduleBuilder.simpleSchedule().withIntervalInSeconds(1).repeatForever()).build();try {Scheduler scheduler = StdSchedulerFactory.getDefaultScheduler();scheduler.scheduleJob(jobDetail,trigger);scheduler.start();} catch (SchedulerException ex) {ex.printStackTrace();}}}

TaskJob.java

import org.quartz.Job;
import org.quartz.JobDataMap;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;public class TaskJob implements Job {@Overridepublic void execute(JobExecutionContext context) throws JobExecutionException {JobDataMap jobDataMap = context.getJobDetail().getJobDataMap();JobDataMap triggerMap = context.getTrigger().getJobDataMap();JobDataMap mergeMap = context.getMergedJobDataMap();System.out.println("jobDataMap => " + jobDataMap.getString("job"));System.out.println("triggerMap => " + triggerMap.getString("trigger"));System.out.println("mergeMap => " + mergeMap.getString("trigger"));}
}

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通过属性赋值

import org.quartz.*;
import org.quartz.impl.StdSchedulerFactory;public class TaskClient {public static void main(String[] args) {JobDetail jobDetail = JobBuilder.newJob(TaskJob.class).withIdentity("job1", "group1").usingJobData("job","jobDetail1.JobDataMap.Value").usingJobData("name","jobDetail1.name.Value") //通过 setName 自动赋值.build();Trigger trigger = TriggerBuilder.newTrigger().withIdentity("trigger1", "trigger1").usingJobData("trigger","trigger.JobDataMap.Value").usingJobData("name","trigger.name.Value")  //如果 Trigger 有值，会覆盖 JobDetail.startNow().withSchedule(SimpleScheduleBuilder.simpleSchedule().withIntervalInSeconds(1).repeatForever()).build();try {Scheduler scheduler = StdSchedulerFactory.getDefaultScheduler();scheduler.scheduleJob(jobDetail,trigger);scheduler.start();} catch (SchedulerException ex) {ex.printStackTrace();}}}

import org.quartz.*;public class TaskJob implements Job {private String name;public void setName(String name) {this.name = name;}@Overridepublic void execute(JobExecutionContext context) throws JobExecutionException {System.out.println("name => " + name);}
}

非并发执行

@
DisallowConcurrentExecution job类上，禁止并发地执行同一个job定义 (JobDetail定义的)的多个实例。

import cn.hutool.core.date.DateUtil;
import org.quartz.*;@DisallowConcurrentExecution
public class TaskJob implements Job {@Overridepublic void execute(JobExecutionContext context) {System.out.println("Time => " + DateUtil.now());try {Thread.sleep(3000);} catch (InterruptedException e) {e.printStackTrace();}}
}

@
PersistJobDataAfterExecution
持久化JobDetail中的JobDataMap（对 trigger 中的 datamap 无效），如果一个任务不是

import cn.hutool.core.date.DateUtil;import org.quartz.*;//持久化JobDetail中的JobDataMap（对 trigger 中的 datamap 无效），如果一个任务不是
@PersistJobDataAfterExecution
public class TaskJob implements Job {@Overridepublic void execute(JobExecutionContext context) {JobDataMap triggerMap = context.getJobDetail().getJobDataMap();triggerMap.put("count", triggerMap.getInt("count") + 1);System.out.println("Time => " + DateUtil.now() + " count =>" + triggerMap.getInt("count"));}
}

Client

import org.quartz.*;
import org.quartz.impl.StdSchedulerFactory;public class TaskClient {public static void main(String[] args) {JobDetail jobDetail = JobBuilder.newJob(TaskJob.class).withIdentity("job1", "group1").usingJobData("job","jobDetail1.JobDataMap.Value").usingJobData("name","jobDetail1.name.Value") //通过 setName 自动赋值.usingJobData("count",0) //通过 setName 自动赋值.build();Trigger trigger = TriggerBuilder.newTrigger().withIdentity("trigger1", "trigger1").usingJobData("trigger","trigger.JobDataMap.Value").usingJobData("name","trigger.name.Value")  //如果 Trigger 有值，会覆盖 JobDetail.startNow().withSchedule(SimpleScheduleBuilder.simpleSchedule().withIntervalInSeconds(1).repeatForever()).build();try {Scheduler scheduler = StdSchedulerFactory.getDefaultScheduler();scheduler.scheduleJob(jobDetail,trigger);scheduler.start();} catch (SchedulerException ex) {ex.printStackTrace();}}}