quartz 定时器学习

Posted on | In |

how2j

1.入门

1.1 几个概念

  • 触发器 Trigger： 什么时候工作 任务 Job: 做什么工作 调度器 Scheduler: 搭配 Trigger和Job

1.2 代码实例

  • 使用quartz定时打印信息
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//静态导入   不用写成JobBuilder.newJob()
import static org.quartz.JobBuilder.newJob;
import static org.quartz.SimpleScheduleBuilder.simpleSchedule;
import static org.quartz.TriggerBuilder.newTrigger;

import org.quartz.JobDetail;
import org.quartz.Scheduler;
import org.quartz.Trigger;
import org.quartz.impl.StdSchedulerFactory;

public class TestQuartz {
    public static void main(String[] args) throws Exception{
            //创建调度器
            Scheduler scheduler = StdSchedulerFactory.getDefaultScheduler();

            //定义一个触发器
            Trigger trigger = newTrigger().withIdentity("trigger1", "group1") //定义名称和所属的组
                .startNow()
                .withSchedule(simpleSchedule()
                    .withIntervalInSeconds(2) //每隔2秒执行一次
                    .withRepeatCount(10)) //总共执行11次(第一次执行不基数)
                .build();

            //定义一个JobDetail
            JobDetail job = newJob(MailJob.class) //指定干活的类MailJob
                .withIdentity("mailjob1", "mailgroup") //定义任务名称和分组
                .usingJobData("email", "admin@10086.com") //定义属性
                .build();

            //调度加入这个job
            scheduler.scheduleJob(job, trigger);

            //启动
            scheduler.start();

            //等待20秒，让前面的任务都执行完了之后，再关闭调度器
            Thread.sleep(20000);
            scheduler.shutdown(true);
    }
}
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package com.how2java;

import java.text.SimpleDateFormat;
import java.util.Date;

import org.quartz.Job;
import org.quartz.JobDetail;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;

public class MailJob implements Job {
    public void execute(JobExecutionContext context) throws JobExecutionException {
        JobDetail detail = context.getJobDetail();
        String email = detail.getJobDataMap().getString("email");

        SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
        String now = sdf.format(new  Date());

        System.out.printf("给邮件地址 %s 发出了一封定时邮件, 当前时间是: %s%n" ,email, now);
    }
}

2.job管理

2.1 job组成部分

  • Job 其实是由 3 个部分组成：JobDetail: 1、用于描述这个Job是做什么/2. 实现Job的类: 具体干活的 3.JobDataMap: 给 Job 提供参数用的
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public class TestQuartz {
    public static void main(String[] args) throws Exception{
            jobDataMap();

    }

    private static void jobDataMap() throws SchedulerException, InterruptedException {
        Scheduler scheduler = StdSchedulerFactory.getDefaultScheduler();

        Trigger trigger = newTrigger().withIdentity("trigger1", "group1")
            .startNow()
            .withSchedule(simpleSchedule()
                .withIntervalInSeconds(2)
                .withRepeatCount(10))
            .build();

        //定义一个JobDetail
        JobDetail job = newJob(MailJob.class)
            .withIdentity("mailjob1", "mailgroup")
            .usingJobData("email", "admin@10086.com")
            .build();

        //用JobDataMap 修改email
        job.getJobDataMap().put("email", "admin@taobao.com");

        //调度加入这个job
        scheduler.scheduleJob(job, trigger);

        //启动
        scheduler.start();

        //等待20秒，让前面的任务都执行完了之后，再关闭调度器
        Thread.sleep(20000);
        scheduler.shutdown(true);
    }
}

2.2 job并发

  • 解决 几个线程同时备份数据库，引发无法预计的混乱
  • @DisallowConcurrentExecution
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@DisallowConcurrentExecution
public class DatabaseBackupJob implements Job {
    public void execute(JobExecutionContext context) throws JobExecutionException {
        JobDetail detail = context.getJobDetail();
        String database = detail.getJobDataMap().getString("database");

        System.out.printf("给数据库 %s 备份, 耗时10秒 %n" ,database);
        try {
            Thread.sleep(10000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}