Quartz.NET开源作业调度框架系列(三):IJobExecutionContext 参数传递

　　前面写了关于Quartz.NET开源作业调度框架的入门和Cron Trigger , 这次继续这个系列, 这次想讨论一下Quartz.NET中的Job如何通过执行上下文(Execution Contex)进行参数传递 , 有些参数想保存状态该如何处理 . 在Quartz.NET中可以用JobDataMap进行参数传递.本例用Quartz.NET的任务来定期轮询数据库表,当数据库的条目达到一定的数目后,进行预警.(其实可以将读取的表和预警条件配置到数据库中的预警条件表中,这样就可以简单实现一个自动预警提醒的小平台).

1 JobWithParametersExample

using System;  2 using System.Threading;  3 
using Common.Logging;  5 using Quartz;  6 using Quartz.Impl;  7 using Quartz.Job;  8 using Quartz.Impl.Calendar;  9 using Quartz.Impl.Matchers; 10 namespace QuartzDemo 11 { 12 
    public class JobWithParametersExample 14  { 15         public string Name 16  { 17             get { return GetType().Name; } 18  } 19         private IScheduler sched = null; 20         public JobWithParametersExample(IScheduler _sched) 21  { 22             sched = _sched; 23  } 24         public virtual void Run() 25  { 26             
            //2S后执行
            DateTimeOffset startTime = DateBuilder.NextGivenSecondDate(null, 2); 29             IJobDetail job1 = JobBuilder.Create<JobWithParameters>() 30                 .WithIdentity("job1", "group1") 31  .Build(); 32 
            ISimpleTrigger trigger1 = (ISimpleTrigger)TriggerBuilder.Create() 34                                                            .WithIdentity("trigger1", "group1") 35  .StartAt(startTime) 36                                                            .WithSimpleSchedule(x => x.WithIntervalInSeconds(5).WithRepeatCount(100)) 37  .Build(); 38 
            // 设置初始参数
            job1.JobDataMap.Put(JobWithParameters.tSQL, "SELECT * FROM [ACT_ID_USER]"); 41             job1.JobDataMap.Put(JobWithParameters.ExecutionCount, 1); 42 
            // 设置监听器
            JobListener listener = new JobListener(); 45             IMatcher<JobKey> matcher = KeyMatcher<JobKey>.KeyEquals(job1.Key); 46  sched.ListenerManager.AddJobListener(listener, matcher); 47 
            // 绑定trigger和job
 sched.ScheduleJob(job1, trigger1); 50             //启动
 sched.Start(); 52         
 } 54  } 55 }

　　JobWithParametersExample用来配置job和trigger,同时定义了一个监听器,来监听定义的job.

2 JobWithParameters

using System;  2 using Common.Logging;  3 using Quartz;  4 using Quartz.Impl;  5 using Quartz.Job;  6 using System.Windows.Forms;  7 namespace QuartzDemo  8 {  9 
 [PersistJobDataAfterExecution] 11  [DisallowConcurrentExecution] 12     public class JobWithParameters : IJob 13  { 14     
        // 定义参数常量
        public const string tSQL = "tSQL"; 17         public const string ExecutionCount = "count"; 18         public const string RowCount = "rowCount"; 19         public const string tableAlert = "tAlert"; 20         // Quartz 每次执行时都会重新实例化一个类, 因此Job类中的非静态变量不能存储状态信息
         private int counter = 1;//都为1 22         //private static int counter = 1;//可以保存状态
        public virtual void Execute(IJobExecutionContext context) 24  { 25            
            JobKey jobKey = context.JobDetail.Key; 27             // 获取传递过来的参数 
            JobDataMap data = context.JobDetail.JobDataMap; 29             string SQL = data.GetString(tSQL); 30             int count = data.GetInt(ExecutionCount); 31 
            if (isOpen("FrmConsole")) 33  { 34                 try
 { 36                     //获取当前Form1实例
                    __instance = (FrmConsole)Application.OpenForms["FrmConsole"]; 38                     //获取当前执行的线程ID
                    __instance.SetInfo(jobKey + "Thread ID " + System.Threading.Thread.CurrentThread.ManagedThreadId.ToString()); 40                     //数据库操作
                    System.Data.DataTable tAlert = SqlHelper.getDateTable(SQL, null); 42                     //回写条数
 data.Put(RowCount, tAlert.Rows.Count); 44                     //通过方法更新消息
                    __instance.SetInfo(string.Format("{0} exec {1} = {2} get {3} rows\r\n execution count (from job map) is {4}\r\n execution count (from job member variable) is {5}", 46  jobKey, 47  tSQL, 48  SQL, 49  tAlert.Rows.Count, 50  count, counter)); 51                     //怎么取出Datatable ? json to datatable 52                     //data.Put(tableAlert, tAlert); 
 } 54                 catch (Exception ex) 55  { 56  Console.WriteLine(ex.Message); 57  } 58  } 59             // 修改执行计数并回写到job data map中
            count++; 61  data.Put(ExecutionCount, count); 62             // 修改本地变量,如果是非静态变量,不能存储状态
            counter++; 64  } 65 
        private static FrmConsole __instance = null; 67      
        /// <summary>
        /// 判断窗体是否打开 70         /// </summary>
        /// <param name="appName"></param>
        /// <returns></returns>
        private bool isOpen(string appName) 74  { 75             FormCollection collection = Application.OpenForms; 76             foreach (Form form in collection) 77  { 78                 if (form.Name == appName) 79  { 80                     return true; 81  } 82  } 83             return false; 84  } 85 
 } 87 }

Quartz 每次执行时都会重新实例化一个类, 因此Job类中的非静态变量不能存储状态信息.如何要保存状态信息可以用静态变量进行处理,也可以用参数值进行传入传出来实现.

3 JobListener

using System;  2 using Common.Logging;  3 using Quartz;  4 using Quartz.Impl;  5 using Quartz.Job;  6 namespace QuartzDemo  7 {  8     public class JobListener : IJobListener  9  { 10    
        public virtual string Name 12  { 13             get { return "JobListener"; } 14  } 15 
        public virtual void JobToBeExecuted(IJobExecutionContext inContext) 17  { 18             //执行前执行
            Console.WriteLine("JobToBeExecuted"); 20  } 21 
        public virtual void JobExecutionVetoed(IJobExecutionContext inContext) 23  { 24             //否决时执行
            Console.WriteLine("JobExecutionVetoed"); 26  } 27 
        public virtual void JobWasExecuted(IJobExecutionContext inContext, JobExecutionException inException) 29  { 30             JobKey jobKey = inContext.JobDetail.Key; 31             // 获取传递过来的参数 
            JobDataMap data = inContext.JobDetail.JobDataMap; 33             //获取回传的数据库表条目数
            int rowCount = data.GetInt(JobWithParameters.RowCount); 35 
            try
 { 38                 if (rowCount > 9) 39  { 40  inContext.Scheduler.PauseAll(); 41                     System.Windows.Forms.MessageBox.Show("预警已超9条"); 42  inContext.Scheduler.ResumeAll(); 43                    
 } 45  Console.WriteLine(rowCount.ToString()); 46  } 47             catch (SchedulerException e) 48  { 49              
 Console.Error.WriteLine(e.StackTrace); 51  } 52  } 53 
 } 55 }

4 效果