在 Quartz.NET 中学习了该框架的用法。
现需要基于该框架升级原本使用 Windows Service 实现的定时任务功能。
原功能使用自定义的系统任务表来保存定时任务的设置，而 Quartz.NET 则使用了一套自己的表，而且没有提供设置的 UI。

为了尽量减少修改量，所以实现的思想是尽量保留原本的任务增删改查功能。
而且经过调查发现，只需在原本处理的后面增加一个更新 Quart.NET 任务的代码就可以了。

下面是示例代码：

1. 设置工程 QuartzSettingApplication

   在该工程中创建 Schedule 但是不启动，将定义好的 Job 增加到 Schedule 中之后就关闭掉该实例。这样修改的设置就可以自动更新到对应的数据库了（这里使用的是 SqlServer）。
   实际项目中只需要在原有的任务设置处理后面增加类似如下 Quartz 的设置处理就可以了。

   using Quartz;
   using Quartz.Impl;
   using Quartz.Logging;
   using QuartzJobs;
   using System;
   using System.Collections.Specialized;
   using System.Threading.Tasks;
   
   namespace QuartzSettingApplication
   {
       class Program
       {
           static void Main(string[] args)
           {
               LogProvider.SetCurrentLogProvider(new ConsoleLogProvider());
   
               // trigger async evaluation
               RunProgram().GetAwaiter().GetResult();
   
               Console.WriteLine("Press any key to close the application");
               Console.ReadKey();
           }
   
           private static async Task RunProgram()
           {
               // Grab the Scheduler instance from the Factory
               NameValueCollection props = new NameValueCollection
                   {
                       { "quartz.serializer.type", "binary" },
                       { "quartz.scheduler.instanceName", "MyScheduler" },
                       { "quartz.jobStore.type", "Quartz.Impl.AdoJobStore.JobStoreTX, Quartz" },
                       { "quartz.jobStore.driverDelegateType", "Quartz.Impl.AdoJobStore.SqlServerDelegate, Quartz" },
                       { "quartz.jobStore.tablePrefix", "QRTZ_" },
                       { "quartz.jobStore.dataSource", "myDS" },
                       { "quartz.dataSource.myDS.connectionString", "Data Source=EDG2GYKVF8G5P6Z;Initial Catalog=Quartz;User ID=sa;Password=password;" },
                       { "quartz.dataSource.myDS.provider", "SqlServer" },
                       { "quartz.threadPool.threadCount", "3" },
                       { "quartz.scheduler.instanceId", "AUTO" },
                       { "quartz.jobStore.clustered", "true" },
                   };
   
               StdSchedulerFactory factory = new StdSchedulerFactory(props);
   
               IScheduler scheduler = await factory.GetScheduler();
               // 删除 Jobs
               for (int i = 0; i <= 2; i++)
               {
                   if (scheduler.CheckExists(new JobKey($"job{ i + 1}", "group1")).GetAwaiter().GetResult())
                   {
                       await scheduler.DeleteJob(new JobKey($"job{ i + 1}", "group1"));
                   }
               }
   
               await Task.Delay(TimeSpan.FromSeconds(10));
   
               // 重新添加 Jobs
               for (int i = 0; i <= 2; i++)
               {
                   if (!scheduler.CheckExists(new JobKey($"job{ i + 1}", "group1")).GetAwaiter().GetResult())
                   {
                       // define the job and tie it to our HelloJob class
                       IJobDetail job = JobBuilder.Create<HelloJob>()
                           .WithIdentity($"job{ i + 1}", "group1")
                           .UsingJobData("count", 2)
                           .Build();
   
                       // Trigger the job to run now, and then repeat every 10 seconds
                       ITrigger trigger = TriggerBuilder.Create()
                           .WithIdentity($"trigger{ i + 1}", "group1")
                           .StartNow()
                           .WithSimpleSchedule(x => x
                               .WithIntervalInSeconds(10)
                               //.WithRepeatCount(0)
                               .RepeatForever()
                               )
                           .Build();
   
                       // Tell quartz to schedule the job using our trigger
                       await scheduler.ScheduleJob(job, trigger);
                   }
               }
   
               await Task.Delay(TimeSpan.FromSeconds(10));
   
               await scheduler.Shutdown();
           }
       }
   }
   

2. 执行 JOB 的工程 QuartzService

   这个是执行 Job 的工程，启动后永不关闭。这个工程可以开启多个实例。
   需要注意的是，这里启用了集群功能，需要保证开启的实例（包括上面设置 Job 时启动的实例）的设置是一样（除了 quartz.threadPool.threadCount），而且服务器系统时间不能有超过 1 秒的误差。

   using Quartz;
   using Quartz.Impl;
   using Quartz.Logging;
   using QuartzJobs;
   using System;
   using System.Collections.Specialized;
   using System.Threading;
   using System.Threading.Tasks;
   
   namespace QuartzService
   {
       class Program
       {
           static void Main(string[] args)
           {
               LogProvider.SetCurrentLogProvider(new ConsoleLogProvider());
   
               // trigger async evaluation
               RunProgram().GetAwaiter().GetResult();
           }
   
           private static async Task RunProgram()
           {
               try
               {
                   // Grab the Scheduler instance from the Factory
                   NameValueCollection props = new NameValueCollection
                   {
                       { "quartz.serializer.type", "binary" },
                       { "quartz.scheduler.instanceName", "MyScheduler" },
                       { "quartz.jobStore.type", "Quartz.Impl.AdoJobStore.JobStoreTX, Quartz" },
                       { "quartz.jobStore.driverDelegateType", "Quartz.Impl.AdoJobStore.SqlServerDelegate, Quartz" },
                       { "quartz.jobStore.tablePrefix", "QRTZ_" },
                       { "quartz.jobStore.dataSource", "myDS" },
                       { "quartz.dataSource.myDS.connectionString", "Data Source=EDG2GYKVF8G5P6Z;Initial Catalog=Quartz;User ID=sa;Password=password;" },
                       { "quartz.dataSource.myDS.provider", "SqlServer" },
                       { "quartz.threadPool.threadCount", "3" },
                       { "quartz.scheduler.instanceId", "AUTO" },
                       { "quartz.jobStore.clustered", "true" },
                   };
   
                   StdSchedulerFactory factory = new StdSchedulerFactory(props);
   
                   //StdSchedulerFactory factory = new StdSchedulerFactory();
                   IScheduler scheduler = await factory.GetScheduler();
   
                   // and start it off
                   await scheduler.Start();
   
                   await Task.Delay(Timeout.Infinite);
   
                   // and last shut down the scheduler when you are ready to close your program
                   await scheduler.Shutdown();
               }
               catch (SchedulerException se)
               {
                   await Console.Error.WriteLineAsync(se.ToString());
               }
           }
       }
   }
   

Quartz.NET 是一个定时计划任务的框架，支持 .NET Core。

本文示例代码大部分来自于官方教程：Quartz.NET - Quartz.NET 3.x Tutorial

Target Framework:.NET Core 2.2
Quartz：3.0.7