使用scheduler之前应首先实例化它。使用SchedulerFactory可以完成scheduler的实例化。用户可直接地实例化这个工厂类并且直接使用工厂的实例(例如下面的例子)。
一旦一个scheduler被实例化,它就可以被启动(start),并且处于驻留模式,直到被关闭(shutdown)。注意,一旦scheduler被关闭(shutdown),则它不能再重新启动,除非重新实例化它。除非scheduler 被启动或者不处于暂停状态,否则触发器不会被触发(任务也不能被执行)。
下面是一个代码片断,这个代码片断实例化并且启动了一个scheduler,接着将一个要执行的任务纳入了进程。
using Common.Logging;
namespace Quartz.Examples.Example1
{
/// <summary>
/// This is just a simple job that says "Hello" to the world.
/// </summary>
/// <author>Bill Kratzer</author>
public class HelloJob : IJob
{
private static ILog _log = LogManager.GetLogger(typeof(HelloJob));
/// <summary>
/// Empty constructor for job initilization
/// <p>
/// Quartz requires a public empty constructor so that the
/// scheduler can instantiate the class whenever it needs.
/// </p>
/// </summary>
public HelloJob()
{
}
/// <summary>
/// Called by the <see cref="IScheduler" /> when a
/// <see cref="Trigger" /> fires that is associated with
/// the <see cref="IJob" />.
/// </summary>
public virtual void Execute(JobExecutionContext context)
{
// Say Hello to the World and display the date/time
_log.Info(string.Format("Hello World! - {0}", System.DateTime.Now.ToString("r")));
}
}
}
ILog log = LogManager.GetLogger( typeof (SimpleExample));
log.Info( " ------- Initializing ---------------------- " );
// First we must get a reference to a scheduler
ISchedulerFactory sf = new StdSchedulerFactory();
IScheduler sched = sf.GetScheduler();
log.Info( " ------- Initialization Complete ----------- " );
log.Info( " ------- Scheduling Jobs ------------------- " );
// computer a time that is on the next round minute
DateTime runTime = TriggerUtils.GetEvenMinuteDate( new NullableDateTime(DateTime.Now));
// define the job and tie it to our HelloJob class
JobDetail job = new JobDetail( " job1 " , " group1 " , typeof (HelloJob));
// Trigger the job to run on the next round minute
SimpleTrigger trigger = new SimpleTrigger( " trigger1 " , " group1 " , runTime);
// Tell quartz to schedule the job using our trigger
sched.ScheduleJob(job, trigger);
log.Info( string .Format( " {0} will run at: {1} " , job.FullName, runTime.ToString( " r " )));
// Start up the scheduler (nothing can actually run until the
// scheduler has been started)
sched.Start();
log.Info( " ------- Started Scheduler ----------------- " );
// wait long enough so that the scheduler as an opportunity to
// run the job!
log.Info( " ------- Waiting 90 seconds
------------- " );
// wait 90 seconds to show jobs
Thread.Sleep( 90 * 1000 );
// shut down the scheduler
log.Info( " ------- Shutting Down --------------------- " );
sched.Shutdown( true );
log.Info( " ------- Shutdown Complete ----------------- " );
如您所见,使用 quartz 相当简单,在第二课中,我们将给出一个 Job 和 Trigger 的快速预览,这样就能够充分理解这个例子。