C# 定时任务 Quartz.NET 的使用

一、定时任务的介绍

相信我们在生活中，大部分都会使用到定时任务去执行自定义的业务逻辑，如：每天早上8点钟发送一份汇总好的财经报告到指定人的邮箱；或者每周一5点30分钟自动执行下载器下载电影，下载完并通过QQ等机器人的方式通知管理员（如下图）。

二、C# 的Quartz.NET的使用

1、NuGet页面搜索Quartz.NET，并安装

2、创建一个 TestJob ，并对 IJob 的接口的实现

/// <summary>
/// 创建一个测试的Job类
/// </summary>
public class TestJob : IJob
{public async Task Execute(IJobExecutionContext context){Console.WriteLine($"{DateTime.Now.ToString("yy-MM-dd HH:mm:ss fff")},执行了TestJob");await Task.CompletedTask;}
}

3、实例化调度器的参数：任务明细，注意：“myGroup” 是任务的一个标识，每一个任务都有独立的一个标识状态

IJobDetail job = JobBuilder.Create<TestJob>().WithIdentity("TestJob", "myGroup").Build();

4、实例化调度器的参数：触发器，如下代码：创建一个一秒循环的触发器

ITrigger trigger = TriggerBuilder.Create().WithIdentity("TestJobTrigger", "myGroup").WithSimpleSchedule(x =>{x.WithIntervalInSeconds(1).RepeatForever();}).Build();

5、创建任务调度器，并执行任务

StdSchedulerFactory factory = new StdSchedulerFactory();
//创建任务调度器
IScheduler scheduler = await factory.GetScheduler();
await scheduler.Start();
await scheduler.ScheduleJob(job, trigger);
Console.WriteLine("任务调度器已启动，按任意键退出...");

6、执行的效果如下：

三、时间表达式 Cron 的使用

官网说明：CronTrigger Tutorial | Quartz.NET

A cron expression is a string comprised of 6 or 7 fields separated by white space. Fields can contain any of the allowed values, along with various combinations of the allowed special characters for that field. The fields are as follows:

Field Name	Mandatory	Allowed Values	Allowed Special Characters
Seconds	YES	0-59	, - * /
Minutes	YES	0-59	, - * /
Hours	YES	0-23	, - * /
Day of month	YES	1-31	, - * ? / L W
Month	YES	1-12 or JAN-DEC	, - * /
Day of week	YES	1-7 or SUN-SAT	, - * ? / L #
Year	NO	empty, 1970-2099	, - * /

So cron expressions can be as simple as this: * * * * ? *

or more complex, like this: 0/5 14,18,3-39,52 * ? JAN,MAR,SEP MON-FRI 2002-2010

Here are some full examples:

Expression	Meaning
`0 0 12 * * ?`	Fire at 12pm (noon) every day
`0 15 10 ? * *`	Fire at 10:15am every day
`0 15 10 * * ?`	Fire at 10:15am every day
`0 15 10 * * ? *`	Fire at 10:15am every day
`0 15 10 * * ? 2005`	Fire at 10:15am every day during the year 2005
`0 * 14 * * ?`	Fire every minute starting at 2pm and ending at 2:59pm, every day
`0 0/5 14 * * ?`	Fire every 5 minutes starting at 2pm and ending at 2:55pm, every day
`0 0/5 14,18 * * ?`	Fire every 5 minutes starting at 2pm and ending at 2:55pm, AND fire every 5 minutes starting at 6pm and ending at 6:55pm, every day
`0 0-5 14 * * ?`	Fire every minute starting at 2pm and ending at 2:05pm, every day
`0 10,44 14 ? 3 WED`	Fire at 2:10pm and at 2:44pm every Wednesday in the month of March.
`0 15 10 ? * MON-FRI`	Fire at 10:15am every Monday, Tuesday, Wednesday, Thursday and Friday
`0 15 10 15 * ?`	Fire at 10:15am on the 15th day of every month
`0 15 10 L * ?`	Fire at 10:15am on the last day of every month
`0 15 10 L-2 * ?`	Fire at 10:15am on the 2nd-to-last last day of every month
`0 15 10 ? * 6L`	Fire at 10:15am on the last Friday of every month
`0 15 10 ? * 6L`	Fire at 10:15am on the last Friday of every month
`0 15 10 ? * 6L 2002-2005`	Fire at 10:15am on every last Friday of every month during the years 2002, 2003, 2004 and 2005
`0 15 10 ? * 6#3`	Fire at 10:15am on the third Friday of every month
`0 0 12 1/5 * ?`	Fire at 12pm (noon) every 5 days every month, starting on the first day of the month.
`0 11 11 11 11 ?`	Fire every November 11th at 11:11am.

如：我想要每天上午10:15分执行一次的cron表达式：0 15 10 * * ?

IJobDetail job = JobBuilder.Create<TestJob>().WithIdentity("TestJob", "myGroup").Build();ITrigger trigger = TriggerBuilder.Create().WithIdentity("TestJobTrigger", "myGroup").WithCronSchedule("0 15 10 * * ?").Build();StdSchedulerFactory factory = new StdSchedulerFactory();
//创建任务调度器
IScheduler scheduler = await factory.GetScheduler();
//启动任务调度器
await scheduler.Start();//将创建的任务和触发器条件添加到创建的任务调度器当中
await scheduler.ScheduleJob(job, trigger);Console.WriteLine("任务调度器已启动，按任意键退出...");
Console.ReadKey();