虽然上一讲中说明,在实际应用中很少用到Quartz实现固定执行次数，但是我就是那个钻牛角尖的人.废话不多，代码如下:
实现思路:
1. 在上一讲中说明Quartz的JobDetail可以是无状态的，也可以是有状态的。Trigger无状态的，所以只能使用JobDetail有状态的子接口StatefulJob.Job代码如下:
package test.quartz.spring;
import java.util.Date;
import org.quartz.Job;
import org.quartz.JobDataMap;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
import org.quartz.StatefulJob;
public class TJob implements StatefulJob {
/**
* 不用挣扎了，Quartz都是无状态的，他不知道执行了几次。
* 如果想要记录状态就需要持久化到数据库.
*/
public void execute(JobExecutionContext cntxt) throws JobExecutionException {
JobDataMap jobDataMap = cntxt.getJobDetail().getJobDataMap();
Integer count = (Integer) jobDataMap.get("count");
if(count==null){
count=0;
}
count++;
System.out.println("杨春龙,太帅了");
System.out.println("不是我说的");
System.out.println( " Generating report - "
+ count
+ "-"
+ new Date());
jobDataMap.put("count", count);
cntxt.getJobDetail().setJobDataMap(jobDataMap);
}
}
根据ApI描述，如果是有状态的Job，所有的Job都共享jobDataMap,所有把执行次数记录下来.虽然我记录了执行次数，但是因为Job是一个Thread，由ThreadPool来维持,那么如何监视Job的执行情况，在看源码中，发现有一个Listener，可以监听进程的执行，代码如下:
package test.quartz.spring;
import org.quartz.CronTrigger;
import org.quartz.JobExecutionContext;
import org.quartz.SchedulerException;
import org.quartz.Trigger;
import org.quartz.listeners.TriggerListenerSupport;
public class TriggerListener extends TriggerListenerSupport {
private String name;
private Integer count;
public void setName(String name)
{
this.name=name;
}
public String getName() {
// TODO Auto-generated method stub
return this.name;
}
public Integer getCount() {
return count;
}
public void setCount(Integer count) {
this.count = count;
}
@Override
public void triggerComplete(Trigger trigger, JobExecutionContext context,
int triggerInstructionCode) {
System.out.println("Trigger :"+trigger.getGroup()+"."+trigger.getName()+" completed with code:"+triggerInstructionCode);
Integer current = (Integer) context.getJobDetail().getJobDataMap().get("count");
System.out.println("调用次数:"+current);
if(current == count){
try {
context.getScheduler().shutdown();
} catch (SchedulerException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
super.triggerComplete(trigger, context, triggerInstructionCode);
}
}
在Job的执行中设置执行次数，在监听器中得到执行次数，当执行次数到达count的时候退出执行.
JobQuartz.xml配置如下
triggerListener 3 test.quartz.spring.TJob
triggerListener 0/10 * * * * ?
在SchedulerFactoryBean中配置监听器列表，在CronTriggerBean配置监听器名称，这样这个监听器就可以监听这个Trigger了，当执行了3次后自动退出
测试代码如下:
package test.quartz.spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestSpring {
/**
* @param args
*/
public static void main(String[] args) {
System.out.println("测试开始");
ApplicationContext ctx = new ClassPathXmlApplicationContext("JobQuartz.xml");
System.out.println("测试结束");
}
}
测试输出如下:
测试开始
2010-09-27 09:33:39,640 INFO [org.springframework.context.support.ClassPathXmlApplicationContext] -2010-09-27 09:33:39,718 INFO [org.springframework.beans.factory.xml.XmlBeanDefinitionReader] - 2010-09-27 09:33:39,781 INFO [org.springframework.context.support.ClassPathXmlApplicationContext] - 2010-09-27 09:33:39,812 INFO [org.springframework.beans.factory.support.DefaultListableBeanFactory] - 2010-09-27 09:33:39,953 INFO [org.quartz.core.SchedulerSignalerImpl] - 2010-09-27 09:33:39,953 INFO [org.quartz.core.QuartzScheduler] - 2010-09-27 09:33:39,953 INFO [org.quartz.simpl.RAMJobStore] - 2010-09-27 09:33:39,953 INFO [org.quartz.core.QuartzScheduler] - 2010-09-27 09:33:39,953 INFO [org.quartz.impl.StdSchedulerFactory] - 2010-09-27 09:33:39,953 INFO [org.quartz.impl.StdSchedulerFactory] - 2010-09-27 09:33:39,953 INFO [org.quartz.core.QuartzScheduler] - 2010-09-27 09:33:39,953 INFO [org.springframework.scheduling.quartz.SchedulerFactoryBean] - 2010-09-27 09:33:39,953 INFO [org.quartz.core.QuartzScheduler] - 测试结束 杨春龙,太帅了 不是我说的 Generating report - 1-Mon Sep 27 09:33:40 CST 2010 Trigger :DEFAULT.cron completed with code:0 调用次数:1 杨春龙,太帅了 不是我说的 Generating report - 2-Mon Sep 27 09:33:50 CST 2010 Trigger :DEFAULT.cron completed with code:0 调用次数:2 杨春龙,太帅了 不是我说的 Generating report - 3-Mon Sep 27 09:34:00 CST 2010 Trigger :DEFAULT.cron completed with code:0 调用次数:3 2010-09-27 09:34:00,000 INFO [org.quartz.core.QuartzScheduler] - 2010-09-27 09:34:00,000 INFO [org.quartz.core.QuartzScheduler] - 2010-09-27 09:34:00,000 INFO [org.quartz.core.QuartzScheduler] -