很多的軟件項目中都會使用到定時任務、定時輪詢數據庫同步，定時郵件通知等功能。.NET Framework具有“內置”定時器功能，通過System.Timers.Timer類。在使用Timer類需要面對的問題：計時器沒有持久化機制；計時器具有不靈活的計劃（僅能設置開始時間和重復間隔，沒有基於日期，時間等）；計時器不使用線程池（每個定時器一個線程）；計時器沒有真正的管理方案 - 你必須編寫自己的機制，以便能夠記住，組織和檢索任務的名稱等。
如果需要在.NET實現定時器的功能，可以嘗試使用以下這款開源免費的組件Quartz.Net組件。目前Quartz.NET版本為3.0，修改了原來的一些問題：修復由於線程本地存儲而不能與AdoJobStore協同工作的調度器信令；線程局部狀態完全刪除；quartz.serializer.type是必需的，即使非序列化RAMJobStore正在使用；JSON序列化錯誤地稱為序列化回調。
Quartz是一個作業調度系統，可以與任何其他軟件系統集成或一起使用。作業調度程序是一個系統，負責在執行預處理程序時執行（或通知）其他軟件組件 - 確定（調度）時間到達。Quartz是非常靈活的，並且包含多個使用范例，可以單獨使用或一起使用，以實現您所需的行為，並使您能夠以您的項目看起來最“自然”的方式編寫代碼。組件的使用非常輕便，並且需要非常少的設置/配置 - 如果您的需求相對基礎，它實際上可以使用“開箱即用”。Quartz是容錯的，並且可以在系統重新啟動之間保留（記住）您的預定作業。盡管Quartz對於在給定的時間表上簡單地運行某些系統進程非常有用，但當您學習如何使用Quartz來驅動應用程序的業務流程時，Quartz的全部潛能可以實現。
Quartz是作為一個小的動態鏈接庫（.dll文件）分發的，它包含所有的核心Quartz功能。 此功能的主要接口（API）是調度程序接口。 它提供簡單的操作，如調度/非調度作業，啟動/停止/暫停調度程序。如果你想安排你自己的軟件組件執行，他們必須實現簡單的Job接口，它包含方法execute（）。 如果希望在計劃的觸發時間到達時通知組件，則組件應實現TriggerListener或JobListener接口。主要的Quartz'進程'可以在您自己的應用程序或獨立應用程序（使用遠程接口）中啟動和運行。
/// <summary>
/// 返回此工廠生成的調度程序的句柄。
/// </summary>
/// <remarks>
///如果<see cref =“Initialize（）”/>方法之一沒有先前調用，然後是默認（no-arg）<see cref =“Initialize（）”/>方法將被這個方法調用。
/// </remarks>
public virtual IScheduler GetScheduler()
{
if (cfg == null)
{
Initialize();
}
SchedulerRepository schedRep = SchedulerRepository.Instance;
IScheduler sched = schedRep.Lookup(SchedulerName);
if (sched != null)
{
if (sched.IsShutdown)
{
schedRep.Remove(SchedulerName);
}
else
{
return sched;
}
}
sched = Instantiate();
return sched;
}
public interface ISchedulerFactory
{
/// <summary>
/// Returns handles to all known Schedulers (made by any SchedulerFactory
/// within this app domain.).
/// </summary>
ICollection<IScheduler> AllSchedulers { get; }
/// <summary>
/// Returns a client-usable handle to a <see cref="IScheduler" />.
/// </summary>
IScheduler GetScheduler();
/// <summary>
/// Returns a handle to the Scheduler with the given name, if it exists.
/// </summary>
IScheduler GetScheduler(string schedName);
}
/// <summary>
/// 獲取或設置與<see cref =“IJob”/>相關聯的<see cref =“JobDataMap”/>。
/// </summary>
public virtual JobDataMap JobDataMap
{
get
{
if (jobDataMap == null)
{
jobDataMap = new JobDataMap();
}
return jobDataMap;
}
set { jobDataMap = value; }
}
[Serializable]
public sealed class JobKey : Key<JobKey>
{
public JobKey(string name) : base(name, null)
{
}
public JobKey(string name, string group) : base(name, group)
{
}
public static JobKey Create(string name)
{
return new JobKey(name, null);
}
public static JobKey Create(string name, string group)
{
return new JobKey(name, group);
}
}
/// <summary>
/// 使用初始化<see cref =“ISchedulerFactory”/>
///給定鍵值集合對象的內容。
/// </summary>
public virtual void Initialize(NameValueCollection props)
{
cfg = new PropertiesParser(props);
ValidateConfiguration();
}
protected virtual void ValidateConfiguration()
{
if (!cfg.GetBooleanProperty(PropertyCheckConfiguration, true))
{
// should not validate
return;
}
// determine currently supported configuration keys via reflection
List<string> supportedKeys = new List<string>();
List<FieldInfo> fields = new List<FieldInfo>(GetType().GetFields(BindingFlags.Static | BindingFlags.Public | BindingFlags.FlattenHierarchy));
// choose constant string fields
fields = fields.FindAll(field => field.FieldType == typeof (string));
// read value from each field
foreach (FieldInfo field in fields)
{
string value = (string) field.GetValue(null);
if (value != null && value.StartsWith(ConfigurationKeyPrefix) && value != ConfigurationKeyPrefix)
{
supportedKeys.Add(value);
}
}
// now check against allowed
foreach (string configurationKey in cfg.UnderlyingProperties.AllKeys)
{
if (!configurationKey.StartsWith(ConfigurationKeyPrefix) || configurationKey.StartsWith(ConfigurationKeyPrefixServer))
{
// don't bother if truly unknown property
continue;
}
bool isMatch = false;
foreach (string supportedKey in supportedKeys)
{
if (configurationKey.StartsWith(supportedKey, StringComparison.InvariantCulture))
{
isMatch = true;
break;
}
}
if (!isMatch)
{
throw new SchedulerConfigException("Unknown configuration property '" + configurationKey + "'");
}
}
}
下面提供一些較為通用的任務處理代碼：
/// <summary>
/// 任務處理幫助類
/// </summary>
public class QuartzHelper
{
public QuartzHelper() { }
public QuartzHelper(string quartzServer, string quartzPort)
{
Server = quartzServer;
Port = quartzPort;
}
/// <summary>
/// 鎖對象
/// </summary>
private static readonly object Obj = new object();
/// <summary>
/// 方案
/// </summary>
private const string Scheme = "tcp";
/// <summary>
/// 服務器的地址
/// </summary>
public static string Server { get; set; }
/// <summary>
/// 服務器的端口
/// </summary>
public static string Port { get; set; }
/// <summary>
/// 緩存任務所在程序集信息
/// </summary>
private static readonly Dictionary<string, Assembly> AssemblyDict = new Dictionary<string, Assembly>();
/// <summary>
/// 程序調度
/// </summary>
private static IScheduler _scheduler;
/// <summary>
/// 初始化任務調度對象
/// </summary>
public static void InitScheduler()
{
try
{
lock (Obj)
{
if (_scheduler != null) return;
//配置文件的方式，配置quartz實例
ISchedulerFactory schedulerFactory = new StdSchedulerFactory();
_scheduler = schedulerFactory.GetScheduler();
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
/// <summary>
/// 啟用任務調度
/// 啟動調度時會把任務表中狀態為“執行中”的任務加入到任務調度隊列中
/// </summary>
public static void StartScheduler()
{
try
{
if (_scheduler.IsStarted) return;
//添加全局監聽
_scheduler.ListenerManager.AddTriggerListener(new CustomTriggerListener(), GroupMatcher<TriggerKey>.AnyGroup());
_scheduler.Start();
//獲取所有執行中的任務
List<TaskModel> listTask = TaskHelper.GetAllTaskList().ToList();
if (listTask.Count > 0)
{
foreach (TaskModel taskUtil in listTask)
{
try
{
ScheduleJob(taskUtil);
}
catch (Exception e)
{
throw new Exception(taskUtil.TaskName,e);
}
}
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
/// <summary>
/// 啟用任務
/// <param name="task">任務信息</param>
/// <param name="isDeleteOldTask">是否刪除原有任務</param>
/// <returns>返回任務trigger</returns>
/// </summary>
public static void ScheduleJob(TaskModel task, bool isDeleteOldTask = false)
{
if (isDeleteOldTask)
{
//先刪除現有已存在任務
DeleteJob(task.TaskID.ToString());
}
//驗證是否正確的Cron表達式
if (ValidExpression(task.CronExpressionString))
{
IJobDetail job = new JobDetailImpl(task.TaskID.ToString(), GetClassInfo(task.AssemblyName, task.ClassName));
//添加任務執行參數
job.JobDataMap.Add("TaskParam", task.TaskParam);
CronTriggerImpl trigger = new CronTriggerImpl
{
CronExpressionString = task.CronExpressionString,
Name = task.TaskID.ToString(),
Description = task.TaskName
};
_scheduler.ScheduleJob(job, trigger);
if (task.Status == TaskStatus.STOP)
{
JobKey jk = new JobKey(task.TaskID.ToString());
_scheduler.PauseJob(jk);
}
else
{
List<DateTime> list = GetNextFireTime(task.CronExpressionString, 5);
foreach (var time in list)
{
LogHelper.WriteLog(time.ToString(CultureInfo.InvariantCulture));
}
}
}
else
{
throw new Exception(task.CronExpressionString + "不是正確的Cron表達式,無法啟動該任務!");
}
}
/// <summary>
/// 初始化 遠程Quartz服務器中的，各個Scheduler實例。
/// 提供給遠程管理端的後台，用戶獲取Scheduler實例的信息。
/// </summary>
public static void InitRemoteScheduler()
{
try
{
NameValueCollection properties = new NameValueCollection
{
["quartz.scheduler.instanceName"] = "ExampleQuartzScheduler",
["quartz.scheduler.proxy"] = "true",
["quartz.scheduler.proxy.address"] =string.Format("{0}://{1}:{2}/QuartzScheduler", Scheme, Server, Port)
};
ISchedulerFactory sf = new StdSchedulerFactory(properties);
_scheduler = sf.GetScheduler();
}
catch (Exception ex)
{
throw new Exception(ex.StackTrace);
}
}
/// <summary>
/// 刪除現有任務
/// </summary>
/// <param name="jobKey"></param>
public static void DeleteJob(string jobKey)
{
try
{
JobKey jk = new JobKey(jobKey);
if (_scheduler.CheckExists(jk))
{
//任務已經存在則刪除
_scheduler.DeleteJob(jk);
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
/// <summary>
/// 暫停任務
/// </summary>
/// <param name="jobKey"></param>
public static void PauseJob(string jobKey)
{
try
{
JobKey jk = new JobKey(jobKey);
if (_scheduler.CheckExists(jk))
{
//任務已經存在則暫停任務
_scheduler.PauseJob(jk);
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
/// <summary>
/// 恢復運行暫停的任務
/// </summary>
/// <param name="jobKey">任務key</param>
public static void ResumeJob(string jobKey)
{
try
{
JobKey jk = new JobKey(jobKey);
if (_scheduler.CheckExists(jk))
{
//任務已經存在則暫停任務
_scheduler.ResumeJob(jk);
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
/// <summary>
/// 獲取類的屬性、方法
/// </summary>
/// <param name="assemblyName">程序集</param>
/// <param name="className">類名</param>
private static Type GetClassInfo(string assemblyName, string className)
{
try
{
assemblyName = FileHelper.GetAbsolutePath(assemblyName + ".dll");
Assembly assembly = null;
if (!AssemblyDict.TryGetValue(assemblyName, out assembly))
{
assembly = Assembly.LoadFrom(assemblyName);
AssemblyDict[assemblyName] = assembly;
}
Type type = assembly.GetType(className, true, true);
return type;
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
/// <summary>
/// 停止任務調度
/// </summary>
public static void StopSchedule()
{
try
{
//判斷調度是否已經關閉
if (!_scheduler.IsShutdown)
{
//等待任務運行完成
_scheduler.Shutdown(true);
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
/// <summary>
/// 校驗字符串是否為正確的Cron表達式
/// </summary>
/// <param name="cronExpression">帶校驗表達式</param>
/// <returns></returns>
public static bool ValidExpression(string cronExpression)
{
return CronExpression.IsValidExpression(cronExpression);
}
/// <summary>
/// 獲取任務在未來周期內哪些時間會運行
/// </summary>
/// <param name="CronExpressionString">Cron表達式</param>
/// <param name="numTimes">運行次數</param>
/// <returns>運行時間段</returns>
public static List<DateTime> GetNextFireTime(string CronExpressionString, int numTimes)
{
if (numTimes < 0)
{
throw new Exception("參數numTimes值大於等於0");
}
//時間表達式
ITrigger trigger = TriggerBuilder.Create().WithCronSchedule(CronExpressionString).Build();
IList<DateTimeOffset> dates = TriggerUtils.ComputeFireTimes(trigger as IOperableTrigger, null, numTimes);
List<DateTime> list = new List<DateTime>();
foreach (DateTimeOffset dtf in dates)
{
list.Add(TimeZoneInfo.ConvertTimeFromUtc(dtf.DateTime, TimeZoneInfo.Local));
}
return list;
}
public static object CurrentTaskList()
{
throw new NotImplementedException();
}
/// <summary>
/// 獲取當前執行的Task 對象
/// </summary>
/// <param name="context"></param>
/// <returns></returns>
public static TaskModel GetTaskDetail(IJobExecutionContext context)
{
TaskModel task = new TaskModel();
if (context != null)
{
task.TaskID = Guid.Parse(context.Trigger.Key.Name);
task.TaskName = context.Trigger.Description;
task.RecentRunTime = DateTime.Now;
task.TaskParam = context.JobDetail.JobDataMap.Get("TaskParam") != null ? context.JobDetail.JobDataMap.Get("TaskParam").ToString() : "";
}
return task;
}
}
public class TaskBll
{
private readonly TaskDAL _dal = new TaskDAL();
/// <summary>
/// 獲取任務列表
/// </summary>
/// <param name="pageIndex"></param>
/// <param name="pageSize"></param>
/// <returns></returns>
public PageOf<TaskModel> GetTaskList(int pageIndex, int pageSize)
{
return _dal.GetTaskList(pageIndex, pageSize);
}
/// <summary>
/// 讀取數據庫中全部的任務
/// </summary>
/// <returns></returns>
public List<TaskModel> GetAllTaskList()
{
return _dal.GetAllTaskList();
}
/// <summary>
///
/// </summary>
/// <param name="taskId"></param>
/// <returns></returns>
public TaskModel GetById(string taskId)
{
throw new NotImplementedException();
}
/// <summary>
/// 刪除任務
/// </summary>
/// <param name="taskId"></param>
/// <returns></returns>
public bool DeleteById(string taskId)
{
return _dal.UpdateTaskStatus(taskId, -1);
}
/// <summary>
/// 修改任務
/// </summary>
/// <param name="taskId"></param>
/// <param name="status"></param>
/// <returns></returns>
public bool UpdateTaskStatus(string taskId, int status)
{
return _dal.UpdateTaskStatus(taskId, status);
}
/// <summary>
/// 修改任務的下次啟動時間
/// </summary>
/// <param name="taskId"></param>
/// <param name="nextFireTime"></param>
/// <returns></returns>
public bool UpdateNextFireTime(string taskId, DateTime nextFireTime)
{
return _dal.UpdateNextFireTime(taskId, nextFireTime);
}
/// <summary>
/// 根據任務Id 修改 上次運行時間
/// </summary>
/// <param name="taskId"></param>
/// <param name="recentRunTime"></param>
/// <returns></returns>
public bool UpdateRecentRunTime(string taskId, DateTime recentRunTime)
{
return _dal.UpdateRecentRunTime(taskId, recentRunTime);
}
/// <summary>
/// 根據任務Id 獲取任務
/// </summary>
/// <param name="taskId"></param>
/// <returns></returns>
public TaskModel GetTaskById(string taskId)
{
return _dal.GetTaskById(taskId);
}
/// <summary>
/// 添加任務
/// </summary>
/// <param name="task"></param>
/// <returns></returns>
public bool Add(TaskModel task)
{
return _dal.Add(task);
}
/// <summary>
/// 修改任務
/// </summary>
/// <param name="task"></param>
/// <returns></returns>
public bool Edit(TaskModel task)
{
return _dal.Edit(task);
}
}
/// <summary>
/// 任務實體
/// </summary>
public class TaskModel
{
/// <summary>
/// 任務ID
/// </summary>
public Guid TaskID { get; set; }
/// <summary>
/// 任務名稱
/// </summary>
public string TaskName { get; set; }
/// <summary>
/// 任務執行參數
/// </summary>
public string TaskParam { get; set; }
/// <summary>
/// 運行頻率設置
/// </summary>
public string CronExpressionString { get; set; }
/// <summary>
/// 任務運頻率中文說明
/// </summary>
public string CronRemark { get; set; }
/// <summary>
/// 任務所在DLL對應的程序集名稱
/// </summary>
public string AssemblyName { get; set; }
/// <summary>
/// 任務所在類
/// </summary>
public string ClassName { get; set; }
public TaskStatus Status { get; set; }
/// <summary>
/// 任務創建時間
/// </summary>
public DateTime? CreatedTime { get; set; }
/// <summary>
/// 任務修改時間
/// </summary>
public DateTime? ModifyTime { get; set; }
/// <summary>
/// 任務最近運行時間
/// </summary>
public DateTime? RecentRunTime { get; set; }
/// <summary>
/// 任務下次運行時間
/// </summary>
public DateTime? NextFireTime { get; set; }
/// <summary>
/// 任務備注
/// </summary>
public string Remark { get; set; }
/// <summary>
/// 是否刪除
/// </summary>
public int IsDelete { get; set; }
}
# You can configure your scheduler in either <quartz> configuration section # or in quartz properties file # Configuration section has precedence quartz.scheduler.instanceName = ExampleQuartzScheduler # configure thread pool info quartz.threadPool.type = Quartz.Simpl.SimpleThreadPool, Quartz quartz.threadPool.threadCount = 10 quartz.threadPool.threadPriority = Normal # job initialization plugin handles our xml reading, without it defaults are used # quartz.plugin.xml.type = Quartz.Plugin.Xml.XMLSchedulingDataProcessorPlugin, Quartz # quartz.plugin.xml.fileNames = ~/quartz_jobs.xml # export this server to remoting context quartz.scheduler.exporter.type = Quartz.Simpl.RemotingSchedulerExporter, Quartz quartz.scheduler.exporter.port = 555 quartz.scheduler.exporter.bindName = QuartzScheduler quartz.scheduler.exporter.channelType = tcp quartz.scheduler.exporter.channelName = httpQuartz
在項目中比較多的使用到定時任務的功能，今天的介紹的組件可以很好的完成一些定時任務的要求。這篇文章主要是作為引子，簡單的介紹了組件的背景和組件的使用方式，如果項目中需要使用，可以進行更加深入的了解。
