怎么在c#中利用socket实现一个心跳超时检测的功能？相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。
1 内存布局图
假设socket3有新的数据到达，需要更新socket3所在的时间轴，处理逻辑如下：
2 处理过程分析：
基本的处理思路就是增加时间轴概念。将socket按最后更新时间排序。因为时间是连续的，不可能将时间分割太细。首先将时间离散，比如属于同一秒内的更新，被认为是属于同一个时间点。离散的时间间隔称为时间刻度，该刻度值可以根据具体情况调整。刻度值越小，超时计算越精确；但是计算量增大。如果时间刻度为10毫秒，则一秒的时间长度被划分为100份。所以需要对更新时间做规整，代码如下：
DateTime CreateNow() { DateTime now = DateTime.Now; int m = 0; if(now.Millisecond != 0) { if(_minimumScaleOfMillisecond == 1000) { now = now.AddSeconds(1); //尾数加1，确保超时值大于 给定的值 } else { //如果now.Millisecond为16毫秒，精确度为10毫秒。则转换后为20毫秒 m = now.Millisecond - now.Millisecond % _minimumScaleOfMillisecond + _minimumScaleOfMillisecond; if(m>=1000) { m -= 1000; now = now.AddSeconds(1); } } } return new DateTime(now.Year, now.Month, now.Day, now.Hour, now.Minute, now.Second,m); }属于同一个时间刻度的socket，被放入在一个哈希表中（见图中Group）。存放socket的类如下：
class SameTimeKeyGroup<T> { DateTime _timeStamp; public DateTime TimeStamp => _timeStamp; public SameTimeKeyGroup(DateTime time) { _timeStamp = time; } public HashSet<T> KeyGroup { get; set; } = new HashSet<T>(); public bool ContainKey(T key) { return KeyGroup.Contains(key); } internal void AddKey(T key) { KeyGroup.Add(key); } internal bool RemoveKey(T key) { return KeyGroup.Remove(key); } }定义一个List表示时间轴：
List<SameTimeKeyGroup<T>> _listTimeScale = new List<SameTimeKeyGroup<T>>();在_listTimeScale 前端的时间较旧，所以链表前端就是有可能超时的socket。
当有socket需要更新时，需要快速知道socket所在的group。这样才能将socket从旧的group移走，再添加到新的group中。需要新增一个链表：
Dictionary<T, SameTimeKeyGroup<T>> _socketToSameTimeKeyGroup = new Dictionary<T, SameTimeKeyGroup<T>>();2.1 当socket有新的数据到达时，处理步骤：
查找socket的上一个群组。如果该群组对应的时刻和当前时刻相同（时间都已经离散，才有可能相同），无需更新时间轴。
从旧的群组删除，增加到新的群组。
public void UpdateTime(T key) { DateTime now = CreateNow(); //是否已存在,从上一个时间群组删除 if (_socketToSameTimeKeyGroup.ContainsKey(key)) { SameTimeKeyGroup<T> group = _socketToSameTimeKeyGroup[key]; if (group.ContainKey(key)) { if (group.TimeStamp == now) //同一时间更新，无需移动 { return; } else { group.RemoveKey(key); _socketToSameTimeKeyGroup.Remove(key); } } } //从超时组 删除 _timeoutSocketGroup.Remove(key); //加入到新组 SameTimeKeyGroup<T> groupFromScaleList = GetOrCreateSocketGroup(now, out bool newCreate); groupFromScaleList.AddKey(key); _socketToSameTimeKeyGroup.Add(key, groupFromScaleList); if (newCreate) { AdjustTimeout(); } }2.2 获取超时的socket
时间轴从旧到新，对比群组的时间与超时时刻。就是链表_listTimeScale，从0开始查找。
/// <summary> ///timeLimit 值为超时时刻限制 ///比如DateTime.Now.AddMilliseconds(-1000);表示 返回一秒钟以前的数据 /// </summary> /// <param name="timeLimit">该时间以前的socket会被返回</param> /// <returns></returns> public List<T> GetTimeoutValue(DateTime timeLimit, bool remove = true) { if((DateTime.Now - timeLimit) > _maxSpan ) { Debug.Write("GetTimeoutSocket timeLimit 参数有误！"); } //从超时组 读取 List<T> result = new List<T>(); foreach(T key in _timeoutSocketGroup) { _timeoutSocketGroup.Add(key); } if(remove) { _timeoutSocketGroup.Clear(); } while (_listTimeScale.Count > 0) { //时间轴从旧到新，查找对比 SameTimeKeyGroup<T> group = _listTimeScale[0]; if(timeLimit >= group.TimeStamp) { foreach (T key in group.KeyGroup) { result.Add(key); if (remove) { _socketToSameTimeKeyGroup.Remove(key); } } if(remove) { _listTimeScale.RemoveAt(0); } } else { break; } } return result; }3 使用举例
//创建变量。最大超时时间为600秒，时间刻度为1秒TimeSpanManage<Socket> _deviceActiveManage = TimeSpanManage<Socket>.Create(TimeSpan.FromSeconds(600), 1000);//当有数据到达时，调用更新函数 _deviceActiveManage.UpdateTime(socket);//需要在线程或定时器中，每隔一段时间调用，找出超时的socket//找出超时时间超过600秒的socket。foreach (Socket socket in _deviceActiveManage.GetTimeoutValue(DateTime.Now.AddSeconds(-600))){ socket.Close();}4 完整代码
/// <summary> /// 超时时间 时间间隔处理 /// </summary> class TimeSpanManage<T> { TimeSpan _maxSpan; int _minimumScaleOfMillisecond; int _scaleCount; List<SameTimeKeyGroup<T>> _listTimeScale = new List<SameTimeKeyGroup<T>>(); private TimeSpanManage() { } /// <summary> /// /// </summary> /// <param name="maxSpan">最大时间时间</param> /// <param name="minimumScaleOfMillisecond">最小刻度（毫秒）</param> /// <returns></returns> public static TimeSpanManage<T> Create(TimeSpan maxSpan, int minimumScaleOfMillisecond) { if (minimumScaleOfMillisecond <= 0) throw new Exception("minimumScaleOfMillisecond 小于0"); if (minimumScaleOfMillisecond > 1000) throw new Exception("minimumScaleOfMillisecond 不能大于1000"); if (maxSpan.TotalMilliseconds <= 0) throw new Exception("maxSpan.TotalMilliseconds 小于0"); TimeSpanManage<T> result = new TimeSpanManage<T>(); result._maxSpan = maxSpan; result._minimumScaleOfMillisecond = minimumScaleOfMillisecond; result._scaleCount = (int)(maxSpan.TotalMilliseconds / minimumScaleOfMillisecond); result._scaleCount++; return result; } Dictionary<T, SameTimeKeyGroup<T>> _socketToSameTimeKeyGroup = new Dictionary<T, SameTimeKeyGroup<T>>(); public void UpdateTime(T key) { DateTime now = CreateNow(); //是否已存在,从上一个时间群组删除 if (_socketToSameTimeKeyGroup.ContainsKey(key)) { SameTimeKeyGroup<T> group = _socketToSameTimeKeyGroup[key]; if (group.ContainKey(key)) { if (group.TimeStamp == now) //同一时间更新，无需移动 { return; } else { group.RemoveKey(key); _socketToSameTimeKeyGroup.Remove(key); } } } //从超时组 删除 _timeoutSocketGroup.Remove(key); //加入到新组 SameTimeKeyGroup<T> groupFromScaleList = GetOrCreateSocketGroup(now, out bool newCreate); groupFromScaleList.AddKey(key); _socketToSameTimeKeyGroup.Add(key, groupFromScaleList); if (newCreate) { AdjustTimeout(); } } public bool RemoveSocket(T key) { bool result = false; if (_socketToSameTimeKeyGroup.ContainsKey(key)) { SameTimeKeyGroup<T> group = _socketToSameTimeKeyGroup[key]; result = group.RemoveKey(key); _socketToSameTimeKeyGroup.Remove(key); } //从超时组 删除 bool result2 = _timeoutSocketGroup.Remove(key); return result || result2; } /// <summary> ///timeLimit 值为超时时刻限制 ///比如DateTime.Now.AddMilliseconds(-1000);表示 返回一秒钟以前的数据 /// </summary> /// <param name="timeLimit">该时间以前的socket会被返回</param> /// <returns></returns> public List<T> GetTimeoutValue(DateTime timeLimit, bool remove = true) { if((DateTime.Now - timeLimit) > _maxSpan ) { Debug.Write("GetTimeoutSocket timeLimit 参数有误！"); } //从超时组 读取 List<T> result = new List<T>(); foreach(T key in _timeoutSocketGroup) { _timeoutSocketGroup.Add(key); } if(remove) { _timeoutSocketGroup.Clear(); } while (_listTimeScale.Count > 0) { //时间轴从旧到新，查找对比 SameTimeKeyGroup<T> group = _listTimeScale[0]; if(timeLimit >= group.TimeStamp) { foreach (T key in group.KeyGroup) { result.Add(key); if (remove) { _socketToSameTimeKeyGroup.Remove(key); } } if(remove) { _listTimeScale.RemoveAt(0); } } else { break; } } return result; } HashSet<T> _timeoutSocketGroup = new HashSet<T>(); private void AdjustTimeout() { while (_listTimeScale.Count > _scaleCount) { SameTimeKeyGroup<T> group = _listTimeScale[0]; foreach (T key in group.KeyGroup) { _timeoutSocketGroup.Add(key); } _listTimeScale.RemoveAt(0); } } private SameTimeKeyGroup<T> GetOrCreateSocketGroup(DateTime now, out bool newCreate) { if (_listTimeScale.Count == 0) { newCreate = true; SameTimeKeyGroup<T> result = new SameTimeKeyGroup<T>(now); _listTimeScale.Add(result); return result; } else { SameTimeKeyGroup<T> lastGroup = _listTimeScale[_listTimeScale.Count - 1]; if (lastGroup.TimeStamp == now) { newCreate = false; return lastGroup; } newCreate = true; SameTimeKeyGroup<T> result = new SameTimeKeyGroup<T>(now); _listTimeScale.Add(result); return result; } } DateTime CreateNow() { DateTime now = DateTime.Now; int m = 0; if(now.Millisecond != 0) { if(_minimumScaleOfMillisecond == 1000) { now = now.AddSeconds(1); //尾数加1，确保超时值大于 给定的值 } else { //如果now.Millisecond为16毫秒，精确度为10毫秒。则转换后为20毫秒 m = now.Millisecond - now.Millisecond % _minimumScaleOfMillisecond + _minimumScaleOfMillisecond; if(m>=1000) { m -= 1000; now = now.AddSeconds(1); } } } return new DateTime(now.Year, now.Month, now.Day, now.Hour, now.Minute, now.Second,m); } } class SameTimeKeyGroup<T> { DateTime _timeStamp; public DateTime TimeStamp => _timeStamp; public SameTimeKeyGroup(DateTime time) { _timeStamp = time; } public HashSet<T> KeyGroup { get; set; } = new HashSet<T>(); public bool ContainKey(T key) { return KeyGroup.Contains(key); } internal void AddKey(T key) { KeyGroup.Add(key); } internal bool RemoveKey(T key) { return KeyGroup.Remove(key); } }看完上述内容，你们掌握怎么在c#中利用socket实现一个心跳超时检测的功能的方法了吗？如果还想学到更多技能或想了解更多相关内容，欢迎关注编程网行业资讯频道，感谢各位的阅读！
