想在.net core中使用定时器功能，需要借助一个服务接口：IHostedService, 继承并实现对应方法，最后再setup.cs类中添加注册服务：services.AddHostedService
下面展示具体代码：
1-公用基类：
public class ModelBase
{ protected IServiceProvider Services { get; set; } protected IWebHostEnvironment WebHostEnvironment { get; set; } ///
/// 配置帮助类 ///
protected ConfigHelper ConfigHelper { get; set; } ///
/// 等同于ASP.NET里面的WebCache(HttpRuntime.Cache) ///
protected IMemoryCache MemoryCache { get; set; } ///
/// 日志 ///
protected ILogger Logger { get; set; } ///
/// 授权帮助 ///
protected OAuthHelper OAuthHelper { get; set; } ///
/// HttpClient帮助工厂 ///
protected IHttpClientFactory HttpClientFactory { get; set; } public ModelBase(params object[] @params)
{ foreach (var item in @params)
{ if (item is IServiceProvider)
{ this.Services = (IServiceProvider)item;
} else if (item is IWebHostEnvironment)
{ this.WebHostEnvironment = (IWebHostEnvironment)item;
} else if (item is ConfigHelper)
{ this.ConfigHelper = (ConfigHelper)item;
} else if (item is IMemoryCache)
{ this.MemoryCache = (IMemoryCache)item;
} else if (item is ILogger)
{ this.Logger = (ILogger)item;
} else if (item is OAuthHelper)
{ this.OAuthHelper = (OAuthHelper)item;
} else if (item is IHttpClientFactory)
{ this.HttpClientFactory = (IHttpClientFactory)item;
}
}
}
}
2-计时器封装类：
相对于.net framework文章计时器部分的类做了对应优化，更加简化了：
using Microsoft.Extensions.Logging;using PaymentAccountAPI.Common;using System;using System.Collections.Generic;using System.Linq;using System.Threading.Tasks;using System.Timers;namespace PaymentAccountAPI.Helper
{ ///
/// 定时周期帮助类 ///
public class TimeCycleHelp : ModelBase
{ public TimeCycleHelp(ILoggerlogger) : base(logger)
{ this.Timer = new System.Timers.Timer();
} ///
/// 服务专属计时器 ///
private System.Timers.Timer Timer; ///
/// 默认计时器时间间隔1秒（提高计时器开始时间准确度） ///
private double DefaultTimerInterval = 1 * 1000; ///
/// 设置多个循环周期 ///
private ListTimeCycleList { get; set; } ///
/// 更新一个计时器的计时周期 ///
/// 新的计时周期
/// 是否是首次更新计时器周期
private void UpdateTimeInterval(double newTimerInterval, bool isFirstStart = false)
{ if (this.Timer != null && newTimerInterval > 0)
{ this.Timer.Stop(); if (this.Timer.Interval != newTimerInterval)
{ this.Timer.Interval = newTimerInterval;
} if (isFirstStart)
{ this.Timer.Elapsed += new System.Timers.ElapsedEventHandler(this.ServiceAction);
} this.Timer.AutoReset = true; this.Timer.Start();
}
} ///
/// 内部辅助方法 ///
///
///
private void ServiceAction(object sender, ElapsedEventArgs e)
{
ListcurrentTimeCycleList = new List(0);
DateTime now = DateTime.Now;
DateTime cycleBeginTime;
DateTime cycleEndTime; foreach (TimeCycle timeCycle in this.TimeCycleList)
{
cycleBeginTime = Convert.ToDateTime(timeCycle.BeginTime);
cycleBeginTime = now.Date.AddHours(cycleBeginTime.Hour).AddMinutes(cycleBeginTime.Minute).AddSeconds(cycleBeginTime.Second);
cycleEndTime = Convert.ToDateTime(timeCycle.EndTime);
cycleEndTime = now.Date.AddHours(cycleEndTime.Hour).AddMinutes(cycleEndTime.Minute).AddSeconds(cycleEndTime.Second); if (cycleEndTime < cycleBeginTime)
{
cycleEndTime = cycleEndTime.AddDays(1);
} if (now >= cycleBeginTime && now <= cycleEndTime)
{ //有最大执行次数限制或者没有限制
if (timeCycle.ActionExecutionTimes < timeCycle.MaxActionTimes || timeCycle.MaxActionTimes == 0)
{
TimeSpan timeSpan = now - cycleBeginTime; bool isCanAction = (int)timeSpan.TotalSeconds % timeCycle.ActionSeconds == 0 ? true : false; if (isCanAction)
{
timeCycle.ActionExecutionTimes++;
currentTimeCycleList.Add(timeCycle);
}
}
} else
{ //不在计时周期内，已执行次数清零
timeCycle.ActionExecutionTimes = 0;
}
} //找到当前循环周期后，执行周期内动作
if (currentTimeCycleList.Count > 0)
{
currentTimeCycleList.ForEach(item =>
{ //使用多线程执行任务，让代码快速执行
Task.Run(() => item.Action());
});
}
} ///
/// 开启计时器 ///
///
public void Start(params TimeCycle[] timeCycleArray)
{ if (timeCycleArray != null && timeCycleArray.Length > 0)
{ if (this.TimeCycleList == null)
{ this.TimeCycleList = new List(100);
} this.TimeCycleList = timeCycleArray.ToList(); //设置首次计时器周期（首次动作执行，是在计时器启动后在设置的时间间隔后做出的动作）
this.UpdateTimeInterval(this.DefaultTimerInterval, true);
}
} ///
/// 结束计时器 ///
public void Stop()
{ this.Timer.Stop();
}
} ///
/// 计时周期类 ///
public class TimeCycle
{ ///
/// 唯一标识 ///
public int ID { get; set; } ///
/// 开始时间(误差1秒=取决于计时器默认时间间隔) ///
public string BeginTime { get; set; } ///
/// 结束时间 ///
public string EndTime { get; set; } ///
/// 最大执行次数 ///
public int MaxActionTimes { get; set; } ///
/// 计时周期内执行的动作(动作会在到达开始时间后的) ///
public Action Action { get; set; } ///
/// 动作执行时间间隔（秒） ///
public int ActionSeconds { get; set; } ///
/// 方法执行次数 ///
internal int ActionExecutionTimes { get; set; } public TimeCycle(int id, Action action, int actionSeconds) : this(id, "00:00:00", action, actionSeconds)
{
} public TimeCycle(int id, string beginTime, Action action, int actionSeconds) : this(id, beginTime, action, actionSeconds, 0)
{
} public TimeCycle(int id, string beginTime, Action action, int actionSeconds, int maxActionTimes) : this(id, beginTime, "23:59:59", action, actionSeconds, maxActionTimes)
{
} ///
/// 基本构造器 ///
/// 唯一标识
/// 开始时间
/// 结束时间
/// 要执行的任务
/// 任务执行时间间隔
/// 最大执行次数
public TimeCycle(int id, string beginTime, string endTime, Action action, int actionSeconds, int maxActionTimes)
{ this.ID = id; this.BeginTime = beginTime; this.EndTime = endTime; this.Action = action; this.ActionSeconds = actionSeconds; this.MaxActionTimes = maxActionTimes;
}
}
}
3-webAPI服务封装类：
using Microsoft.Extensions.Hosting;using Microsoft.Extensions.Logging;using PaymentAccountAPI.Common;using PaymentAccountAPI.Helper;using PaymentAccountAPI.PaymentAccountHelper;using System;using System.Threading;using System.Threading.Tasks;namespace PaymentAccountAPI.Hangfire
{ public class SyncToCMSService : ModelBase, IHostedService
{private TimeCycleHelp _TimeCycleHelp { get; set; } public SyncToCMSService(ConfigHelper configHelper,
TimeCycleHelp timeCycleHelp, ILoggerlogger) : base(logger, configHelper)
{this._TimeCycleHelp = timeCycleHelp;
} public void SyncData()
{ //...需要执行的任务代码
this.Logger.LogInformation($"定时任务：完成{currentDate.ToShortDateString()}的交易记录同步！");
} public Task StartAsync(CancellationToken cancellationToken)
{ this.Logger.LogInformation($"定时任务：同步服务已启动..."); //正式代码
string syncBeginTime = this.ConfigHelper.GetAppSettingValue("SyncCMSBeginTime"); string syncEndTime = this.ConfigHelper.GetAppSettingValue("SyncCMSEndTime"); this._TimeCycleHelp.Start(new TimeCycle(999, syncBeginTime, syncEndTime, this.SyncData, 3600, 2)); //测试代码 //this._TimeCycleHelp.Start(new TimeCycle(999, "12:00:00", () => //{ // this.Logger.LogInformation("test123"); //}, 10, 3));
return Task.CompletedTask;
} public Task StopAsync(CancellationToken cancellationToken)
{ this.Logger.LogInformation($"同步服务已停止..."); this._TimeCycleHelp.Stop(); return Task.CompletedTask;
}
}
}
4-在startup.cs添加注册服务：
#region 添加定时任务 services.AddSingleton(); services.AddHostedService(); #endregion
5-部署到IIS站点项目时的注意事项（引用下面道友的一段话）：
关于GenericHost的生存周期问题
如果你使用的是控制台启动，则此问题暂时可以忽略。
如果你使用的是站点项目，并且还是通过IIS启动，那么你可能要注意了，因为.net core 的站点自身是有HOST宿主处理，IIS是其上代理，其启动关闭，端口映射等由IIS内部完成。所以其依然受限于IIS的闲置回收影响，当IIS闲置回收时，其后的.Net Host也会被一同关闭，需要有新的请求进来时才会再次启动。不过鉴于当前任务处理已经如此简单，有个取巧的做法，实现一个站点自身的心跳检测任务，IIS默认20分钟回收，任务时间可以设为15分钟（你也可以设置IIS站点回收时间），当然如果你的任务如果没有那么严格的时间要求你也可以不用处理，因为回收后一旦接受到新的请求，任务会再次发起。
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