下面简单的helloword代码感受一下Quartz的工作流程:
package quartz; import java.util.Date; import org.quartz.Job; import org.quartz.JobExecutionContext; import org.quartz.JobExecutionException; public class HelloWord implements Job{ //实现自己的定时方法 public void execute(JobExecutionContext arg0) throws JobExecutionException { System.out.println("hello world " + new Date()); } }
package quartz; import java.util.Date; import org.quartz.JobBuilder; import org.quartz.JobDetail; import org.quartz.Scheduler; import org.quartz.SchedulerException; import org.quartz.Trigger; import org.quartz.TriggerBuilder; import org.quartz.impl.StdSchedulerFactory; public class SimpleExample { public static void main(String[] args) throws SchedulerException{ SimpleExample example=new SimpleExample(); example.run(); } public void run() throws SchedulerException { //获取scheduler实例 Scheduler scheduler=StdSchedulerFactory.getDefaultScheduler(); scheduler.start(); //当前时间 Date runTime=new Date(); //定义一个 job 对象并绑定我们写的 HelloWord 类 // 真正执行的任务并不是Job接口的实例,而是用反射的方式实例化的一个JobDetail实例 JobDetail job=JobBuilder.newJob(HelloWord.class).withIdentity("job1","group1").build(); // 定义一个触发器,startAt方法定义了任务应当开始的时间 .即下一个整数分钟执行 Trigger trigger=TriggerBuilder.newTrigger().withIdentity("trigger1","group1").startAt(runTime).build(); // 将job和Trigger放入scheduler scheduler.scheduleJob(job, trigger); //启动 scheduler.start(); try { Thread.sleep(100); } catch (InterruptedException e) { e.printStackTrace(); scheduler.shutdown(); } } }在实际web应用中,我们可用通过使用spring框架来使用Quartz实现定时任务,而且很方便,一共有三种方式:
否则会报错)org.springframework spring-context-support 3.2.8.RELEASE
package spring.demo.pojo; import org.quartz.JobExecutionContext; import org.quartz.JobExecutionException; import org.springframework.scheduling.quartz.QuartzJobBean; //继承QuartzJobBean,并重写executeInternal方法 public class QuartzTask extends QuartzJobBean{ private int timeout; private static int i = 0; //调度工厂实例化后,经过timeout时间开始执行调度 public void setTimeout(int timeout) { this.timeout = timeout; } @Override protected void executeInternal(JobExecutionContext context) throws JobExecutionException { System.out.println("task running..."+ ++i + "进行中..."); } }
10,15,20,25,30,35,40,45,50,55 * * * * ?
package spring.demo.pojo; public class QuartzJob { public void work(){ System.out.println("work running..."); } }
work
10,15,20,25,30,35,40,45,50,55 * * * * ?
3.第三种方式,通过@Scheduled注解的方式实现,需要修改applicationContext.xml三个部分内容:
1.xmlns添加:
xmlns:task="http://www.springframework.org/schema/task"
2.xsi:schemaLocation添加:
http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.1.xsd3.applicationContext.xml中添加:
最后在我们的定时任务上添加上@Scheduled注解即可,一般都采用cronTrigger方式,即@Scheduled(cron=“相应的定时表达式”)
package spring.demo.service; import org.springframework.context.support.ClassPathXmlApplicationContext; import org.springframework.scheduling.annotation.Scheduled; import org.springframework.stereotype.Service; @Service public class QuartzService { @Scheduled(cron = "0/2 * * * * *") public void process() { System.out.println("job run..."); } public static void main(String[] args) throws InterruptedException { ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml"); while (true) { System.out.println("main running..."); Thread.sleep(10000); } } }个人建议采用第二种和第三种的方式实现Quartz比较简洁方便,下面顺便在网上查阅关于cron表达式的资料,不过我记得好像有一些工具可以方便生成这些表达式(Visual Cron Editor)目前没有具体的研究过,当然有些表达式也可以百度查阅到:
Cron表达式包含6个必要组件和一个可选组件,如下表所示: