Quartz深入浅出(二)

package org.quartz.examples.examples01;

import java.util.Date;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.quartz.Job;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;

/**
 * hello world Quartz
 * @author weeks
 *
 */
public class HelloJob implements Job {

    private static Logger _log = LoggerFactory.getLogger(HelloJob .class );

    /**
     * Job，Job需要一个公有的构造函数，否则Factory无法构建
     */
    public HelloJob() {
    }

    /**
     * 实现execute方法
     */
    public void execute(JobExecutionContext context)
        throws JobExecutionException {
        _log.info( "Hello World! - " + new Date());
    }

}

package org.quartz.examples.examples01;

import static org.quartz.DateBuilder.evenMinuteDate ;
import static org.quartz.JobBuilder.newJob ;
import static org.quartz.TriggerBuilder.newTrigger ;
import org.quartz.JobDetail;
import org.quartz.Scheduler;
import org.quartz.SchedulerFactory;
import org.quartz.Trigger;
import org.quartz.impl.StdSchedulerFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Date;

/**
 * 此Demo将演示如何启动和关闭Quartz调度器，以及如何运作
 * @author weeks
 *
 */
public class SimpleExample {

  public void run() throws Exception {
    Logger log = LoggerFactory.getLogger(SimpleExample.class);

    log.info("------- Initializing ----------------------");

    // 1、工厂模式 构建Scheduler的Factory，其中STD为Quartz默认的Factory，开发者亦可自行实现自己的Factory;Job、Trigger等组件
    SchedulerFactory sf = new StdSchedulerFactory();
    // 2、通过SchedulerFactory获得Scheduler对象
    Scheduler sched = sf.getScheduler();

    log.info("------- Initialization Complete -----------");

    // 3、org.quartz.DateBuilder.evenMinuteDate <下一分钟>  -- 通过DateBuilder构建Date
    Date runTime = evenMinuteDate(new Date());

    log.info("------- Scheduling Job  -------------------");

    // 4、org.quartz.JobBuilder.newJob --通过JobBuilder构建Job
    JobDetail job = newJob(HelloJob.class).withIdentity("job1", "group1").build();

    // 5、通过TriggerBuilder进行构建
    Trigger trigger = newTrigger().withIdentity("trigger1" , "group1").startAt(runTime ).build();

    // 6、工厂模式，组装各个组件<JOB，Trigger>
    sched.scheduleJob(job, trigger);
   
    // [group1.job1] will run at:
    log.info(job.getKey() + " will run at: " + runTime);

    // 7、start
    sched.start();

    log.info("------- Started Scheduler -----------------");

    log.info("------- Waiting 65 seconds... -------------");
    try {
      // wait 65 seconds to show job
      Thread.sleep(65L * 1000L);
      // executing...
    } catch (Exception e) {
      //
    }

    // shut down the scheduler
    log.info("------- Shutting Down ---------------------");
    // 8、通过Scheduler销毁内置的Trigger和Job
    sched.shutdown(true);
    log.info("------- Shutdown Complete -----------------");
  }

  public static void main(String[] args) throws Exception {

    SimpleExample example = new SimpleExample();
    example.run();

  }

}

1.   void execute(JobExecutionContext  context)  throws JobExecutionException;
2.   当Quartz调度器到约定的时间，它就会生成一个Job的实例，所以你实现Job接口　必须提供一个公有函数，否则会抛出异常，并调用execute方法．其中调度器只管执行，而不关心结果，除非抛出JobExecutionException异常．
3. 　JobExecutionContext 中封装有Quartz运行所需要的所有信息，可以参见下面具体的代码片段．

1. 其中Scheduler调度器对象，它的方法有start()、shutdown()等方法，负责管理整个调度作业．
2. Job 又与几个对象有关 Job、JobDetail、JobDataMap
   1. 通过类图来看他们之间的关系
   2. 
      
   3. 通过类图可以很明显的看出由JobExecutionContext来组装各个子组件，我们看看JobExecutionContextImpl的源代码，它保存着所有上下文信息

   4.     private transient Scheduler scheduler ;
      
          private Trigger trigger;
      
          private JobDetail jobDetail;
         
          private JobDataMap jobDataMap;
      
          private transient Job job;
         
          private Calendar calendar;
      
          private boolean recovering = false;
      
          private int numRefires = 0;
      
          private Date fireTime;
      
          private Date scheduledFireTime;
      
          private Date prevFireTime;
      
          private Date nextFireTime;
         
          private long jobRunTime = -1;
         
          private Object result;
         
          private HashMap<Object, Object> data=new HashMap<Object, Object>();

   5. 关于JobDetail
      1. JobDetail不存储具体的实例，但它允许你定义一个实例，JobDetail 又指向JobDataMap
      2. JobDetail持有Job的详细信息，如它所属的组，名称等信息
   6. 关于JobDataMap
      1. JobDataMap保存着任务实例的对象，并保持着他们状态信息，它是Ｍap接口的实现，即你可以往里面put和get一些你想存储和获取的信息．
3. 关于Trigger
   1. 即根据具体约定的触发器，具体的如：SimpleTrigger、CronTrigger　等