quartz使用案例篇【面试+工作】
作业被安排在一个给定的触发时运行。触发器可以使用以下指令的接近任何组合来创建:
作业是由其创建者赋予的名字,也可以组织成命名组。触发器也可以给予名称和放置在组中,以方便地将它们调度内组织。作业可以被添加到所述调度器一次,而是具有多个触发器注册。在企业Java环境中,作业可以执行自己的工作作为分布式(XA)事务的一部分。
Quartz, 是一个企业级调度工作的框架,帮助Java应用程序到调度工作/任务在指定的日期和时间运行。
本教程教作为一个入门介绍如何开发使用调度工作(在写本教程时使用的最新Quartz 2.2.1 )
可以从官方网站或Maven中央存储库下载Quartz库文件;
File : quartz.properties
org.quartz.scheduler.instanceName = MyScheduler
org.quartz.threadPool.threadCount = 3
org.quartz.jobStore.class =org.quartz.simpl.RAMJobStore
Quartz作业定义要运行什么?
File : HelloJob
package cn.com.javahelp.common;
import org.quartz.Job;import org.quartz.JobExecutionContext;import org.quartz.JobExecutionException;
public class HelloJob implements Job{
public void execute(JobExecutionContext context)
throws JobExecutionException {
System.out.println("Hello Quartz!");
}}
定义Quartz触发器,当Quartz运行在上面的Quartz作业。
像老版本的Quartz,仍然有两种类型的触发器在Quartz2,但API有些变化:
· SimpleTrigger – 允许设置开始时间,结束时间,重复间隔。
· CronTrigger – 允许UNIX cron表达式来指定日期和时间来运行作业。
SimpleTrigger – 每5秒运行。
Trigger trigger = TriggerBuilder
.newTrigger()
.withIdentity("dummyTriggerName", "group1")
.withSchedule(
SimpleScheduleBuilder.simpleSchedule()
.withIntervalInSeconds(5).repeatForever())
.build();
CronTrigger – 每5秒运行。
Trigger trigger = TriggerBuilder
.newTrigger()
.withIdentity("dummyTriggerName", "group1")
.withSchedule(
CronScheduleBuilder.cronSchedule("0/5 * * * * ?"))
.build();
注意 请阅读 官方文档 更多的Quartz2触发器的例子。
调度类链接“工作”和“触发器”到一起,并执行它。
Scheduler scheduler = new StdSchedulerFactory().getScheduler();
scheduler.start();
scheduler.scheduleJob(job, trigger);
Quartz2 两个 SimpleTrigger 和 CronTrigger 完整的例子。
SimpleTrigger的例子 - 每间隔5秒运行。
package cn.com.javahelp.quartz;
import org.quartz.JobBuilder;
import org.quartz.JobDetail;
import org.quartz.Scheduler;
import org.quartz.SimpleScheduleBuilder;
import org.quartz.Trigger;
import org.quartz.TriggerBuilder;
import org.quartz.impl.StdSchedulerFactory;
public class SimpleTriggerExample {
public static void main(String[] args) throws Exception {
// Quartz 1.6.3
// JobDetail job = new JobDetail();
// job.setName("dummyJobName");
// job.setJobClass(HelloJob.class);
JobDetail job = JobBuilder.newJob(HelloJob.class)
.withIdentity("dummyJobName", "group1").build();
//Quartz 1.6.3
// SimpleTrigger trigger = new SimpleTrigger();
// trigger.setStartTime(new Date(System.currentTimeMillis() + 1000));
// trigger.setRepeatCount(SimpleTrigger.REPEAT_INDEFINITELY);
// trigger.setRepeatInterval(30000);
// Trigger the job to run on the next round minute
Trigger trigger = TriggerBuilder
.newTrigger()
.withIdentity("dummyTriggerName", "group1")
.withSchedule(
SimpleScheduleBuilder.simpleSchedule()
.withIntervalInSeconds(5).repeatForever())
.build();
// schedule it
Scheduler scheduler = new StdSchedulerFactory().getScheduler();
scheduler.start();
scheduler.scheduleJob(job, trigger);
}}
CronTrigger例子 - 同样,在每5秒运行作业。
package cn.com.javahelp.quartz;
import org.quartz.CronScheduleBuilder;
import org.quartz.JobBuilder;
import org.quartz.JobDetail;
import org.quartz.Scheduler;
import org.quartz.Trigger;
import org.quartz.TriggerBuilder;
import org.quartz.impl.StdSchedulerFactory;
public class CronTriggerExample {
public static void main( String[] args ) throws Exception
{
//Quartz 1.6.3
//JobDetail job = new JobDetail();
//job.setName("dummyJobName");
//job.setJobClass(HelloJob.class);
JobDetail job = JobBuilder.newJob(HelloJob.class)
.withIdentity("dummyJobName", "group1").build();
//Quartz 1.6.3
//CronTrigger trigger = new CronTrigger();
//trigger.setName("dummyTriggerName");
//trigger.setCronExpression("0/5 * * * * ?");
Trigger trigger = TriggerBuilder
.newTrigger()
.withIdentity("dummyTriggerName", "group1")
.withSchedule(
CronScheduleBuilder.cronSchedule("0/5 * * * * ?"))
.build();
//schedule it
Scheduler scheduler = new StdSchedulerFactory().getScheduler();
scheduler.start();
scheduler.scheduleJob(job, trigger);
}}
我们将展示/介绍如何创建一个JobListener,跟踪运行工作状态在作业完成等。
P.S 这个例子是Quartz 2.1.5
作业 - 用于打印一个简单的信息,并抛出一个JobExecutionException进行测试。
File : HelloJob.java
package cn.com.javahelp;
import org.quartz.Job;import org.quartz.JobExecutionContext;import org.quartz.JobExecutionException;
public class HelloJob implements Job{
public void execute(JobExecutionContext context)
throws JobExecutionException {
System.out.println("Hello Quartz! - by yiibai.com");
//Throw exception for testing
throw new JobExecutionException("Testing Exception");
}
}
创建一个JobListener,只是实现了JobListener接口,并覆盖所有的接口的方法。
File : HelloJobListener.java
package cn.com.javahelp.quartz.listener;
import org.quartz.JobExecutionContext;import org.quartz.JobExecutionException;import org.quartz.JobListener;
public class HelloJobListener implements JobListener {
public static final String LISTENER_NAME = "dummyJobListenerName";
@Override
public String getName() {
return LISTENER_NAME; //must return a name
}
// Run this if job is about to be executed.
@Override
public void jobToBeExecuted(JobExecutionContext context) {
String jobName = context.getJobDetail().getKey().toString();
System.out.println("jobToBeExecuted");
System.out.println("Job : " + jobName + " is going to start...");
}
// No idea when will run this?
@Override
public void jobExecutionVetoed(JobExecutionContext context) {
System.out.println("jobExecutionVetoed");
}
//Run this after job has been executed
@Override
public void jobWasExecuted(JobExecutionContext context,
JobExecutionException jobException) {
System.out.println("jobWasExecuted");
String jobName = context.getJobDetail().getKey().toString();
System.out.println("Job : " + jobName + " is finished...");
if (!jobException.getMessage().equals("")) {
System.out.println("Exception thrown by: " + jobName
+ " Exception: " + jobException.getMessage());
}
}
}
注意: 不知道什么是“jobExecutionVetoed”,并会在何时触发?
例如上面HelloJobListener连接到调度和监控作业的状态。
File : CronTriggerExample.java
package cn.com.javahelp.quartz;
import org.quartz.CronScheduleBuilder;
import org.quartz.JobBuilder;
import org.quartz.JobDetail;
import org.quartz.JobKey;
import org.quartz.Scheduler;
import org.quartz.Trigger;
import org.quartz.TriggerBuilder;
import org.quartz.impl.StdSchedulerFactory;
import org.quartz.impl.matchers.KeyMatcher;
import cn.com.javahelp.quartz.listener.HelloJobListener;
public class CronTriggerExample {
public static void main( String[] args ) throws Exception
{
JobKey jobKey = new JobKey("dummyJobName", "group1");
JobDetail job = JobBuilder.newJob(HelloJob.class)
.withIdentity(jobKey).build();
Trigger trigger = TriggerBuilder
.newTrigger()
.withIdentity("dummyTriggerName", "group1")
.withSchedule(
CronScheduleBuilder.cronSchedule("0/5 * * * * ?"))
.build();
Scheduler scheduler = new StdSchedulerFactory().getScheduler();
//Listener attached to jobKey
scheduler.getListenerManager().addJobListener(
new HelloJobListener(), KeyMatcher.keyEquals(jobKey)
);
//Listener attached to group named "group 1" only.
//scheduler.getListenerManager().addJobListener(
// new HelloJobListener(), GroupMatcher.jobGroupEquals("group1")
//);
scheduler.start();
scheduler.scheduleJob(job, trigger);
}}
运行CronTriggerExample.java, 这里是输出结果:
jobToBeExecuted
Job : group1.dummyJobName is going to start...
Hello Quartz! - by yiibai.com
jobWasExecuted
Job : group1.dummyJobName is started and finished...
Exception thrown by: group1.dummyJobName Exception: Testing Exception
jobToBeExecuted
Job : group1.dummyJobName is going to start...
Hello Quartz! - by yiibai.com
jobWasExecuted
Job : group1.dummyJobName is started and finished...
Exception thrown by: group1.dummyJobName Exception: Testing Exception
在这个例子中,我们将介绍如何通过Quartz API 多个作业。在Quartz调度框架中,每个作业将被连接到一个唯一的触发,并且由调度器运行它。
P.S:在 Quartz 中,一个触发器触发多个作业是不可以的。
创建3个作业,JobA,JobB和JobC。
package cn.com.javahelp.quartz;
import org.quartz.Job;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
public class JobA implements Job {
@Override
public void execute(JobExecutionContext context)
throws JobExecutionException {
System.out.println("Job A is runing //every 5 seconds ");
}
}
package cn.com.javahelp.quartz;
import org.quartz.Job;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
public class JobB implements Job {
@Override
public void execute(JobExecutionContext context)
throws JobExecutionException {
System.out.println("Job B is runing");
}
}
package cn.com.javahelp.quartz;
import org.quartz.Job;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
public class JobC implements Job {
@Override
public void execute(JobExecutionContext context)
throws JobExecutionException {
System.out.println("Job C is runing");
}
}
使用QuartzAPI声明上述3个作业,分配它们到特定触发器并调度它。
package cn.com.javahelp.quartz;
import org.quartz.CronScheduleBuilder;
import org.quartz.JobBuilder;
import org.quartz.JobDetail;
import org.quartz.JobKey;
import org.quartz.Scheduler;
import org.quartz.Trigger;
import org.quartz.TriggerBuilder;
import org.quartz.impl.StdSchedulerFactory;
public class CronTriggerExample {
public static void main( String[] args ) throws Exception
{
JobKey jobKeyA = new JobKey("jobA", "group1");
JobDetail jobA = JobBuilder.newJob(JobA.class)
.withIdentity(jobKeyA).build();
JobKey jobKeyB = new JobKey("jobB", "group1");
JobDetail jobB = JobBuilder.newJob(JobB.class)
.withIdentity(jobKeyB).build();
JobKey jobKeyC = new JobKey("jobC", "group1");
JobDetail jobC = JobBuilder.newJob(JobC.class)
.withIdentity(jobKeyC).build();
Trigger trigger1 = TriggerBuilder
.newTrigger()
.withIdentity("dummyTriggerName1", "group1")
.withSchedule(
CronScheduleBuilder.cronSchedule("0/5 * * * * ?"))
.build();
Trigger trigger2 = TriggerBuilder
.newTrigger()
.withIdentity("dummyTriggerName2", "group1")
.withSchedule(
CronScheduleBuilder.cronSchedule("0/5 * * * * ?"))
.build();
Trigger trigger3 = TriggerBuilder
.newTrigger()
.withIdentity("dummyTriggerName3", "group1")
.withSchedule(
CronScheduleBuilder.cronSchedule("0/5 * * * * ?"))
.build();
Scheduler scheduler = new StdSchedulerFactory().getScheduler();
scheduler.start();
scheduler.scheduleJob(jobA, trigger1);
scheduler.scheduleJob(jobB, trigger2);
scheduler.scheduleJob(jobC, trigger3);
}}
输出结果如上:
Job A is runing //every 5 seconds
Job B is runing
Job C is runing
Job A is runing //every 5 seconds
Job B is runing
Job C is runing
下面是两个代码片段展示如何列出所有Quartz的作业。Quartz2 API都发生了很大变化,所以语法和Quartz1.x是不同的
Scheduler scheduler = new StdSchedulerFactory().getScheduler();
for (String groupName : scheduler.getJobGroupNames()) {
for (JobKey jobKey : scheduler.getJobKeys(GroupMatcher.jobGroupEquals(groupName))) {
String jobName = jobKey.getName();
String jobGroup = jobKey.getGroup();
//get job's trigger
List<Trigger> triggers = (List<Trigger>) scheduler.getTriggersOfJob(jobKey);
Date nextFireTime = triggers.get(0).getNextFireTime();
System.out.println("[jobName] : " + jobName + " [groupName] : "
+ jobGroup + " - " + nextFireTime);
}
}
Scheduler scheduler = new StdSchedulerFactory().getScheduler();
//loop all group
for (String groupName : scheduler.getJobGroupNames()) {
//loop all jobs by groupname
for (String jobName : scheduler.getJobNames(groupName)) {
//get job's trigger
Trigger[] triggers = scheduler.getTriggersOfJob(jobName,groupName);
Date nextFireTime = triggers[0].getNextFireTime();
System.out.println("[jobName] : " + jobName + " [groupName] : "
+ groupName + " - " + nextFireTime);
}
}