最近编码的过程中，使用了对象本地内存缓存，缓存用了Dictionary<string,object>, ConcurrentDictionary<string,oject>,还可以是MemoryCache(底层基于Hashtable)。使用缓存，肯定要处理数据变化缓存同步的问题。如何比较数据的变化，演进为新的内存对象数据和已有内存对象数据的相等性比较！
对象的Equals相等性比较，百度、google会有一大堆实现，几个重点的点：
1. 实现接口IEquatable<T>
https://msdn.microsoft.com/en-us/library/ms131190(v=vs.110).aspx
2.重写bool Equals(object other)方法和 int GetHashCode()方法
http://stackoverflow.com/questions/2734914/whats-the-difference-between-iequatable-and-just-overriding-object-equals
这里直接贴出来一个通用实现，分享给大家：
1 /// <summary> 2 /// 流控事件 3 /// </summary> 4 [Serializable] 5 public class FlowControlEvent: IEquatable<FlowControlEvent> 6 { 7 public static readonly string Global = "Global"; 8 9 /// <summary> 10 /// 标识 11 /// </summary> 12 public string ID { get; set; } 13 14 /// <summary> 15 /// 流控策略名称 16 /// </summary> 17 public string StrategyName { get; set; } 18 19 /// <summary> 20 /// 是否手工触发 21 /// </summary> 22 public bool IsManuelTrigger { get; set; } 23 24 /// <summary> 25 /// 触发时间 26 /// </summary> 27 public DateTime TriggerTime { get; set; } 28 29 /// <summary> 30 /// 流控策略 31 /// </summary> 32 public FlowControlStrategy Strategy { get; set; } 33 34 /// <summary> 35 /// 持续时间，单位s 36 /// </summary> 37 public long Duration { get; set; } 38 39 //是否启用 40 private bool isEnable = true; 41 42 /// <summary> 43 /// 是否启用 44 /// </summary> 45 public bool IsEnable 46 { 47 get 48 { 49 return isEnable; 50 } 51 set 52 { 53 isEnable = value; 54 } 55 } 56 57 /// <summary> 58 /// 是否使用中 59 /// </summary> 60 public bool IsUsing 61 { 62 get 63 { 64 if (IsEnable == false) return false; 65 if (IsManuelTrigger) 66 { 67 if (Duration == long.MaxValue) 68 { 69 return true; 70 } 71 else 72 { 73 var span = DateTime.Now - TriggerTime; 74 if (span.TotalSeconds > Duration) 75 return false; 76 else 77 return true; 78 } 79 } 80 else 81 { 82 return true; 83 } 84 } 85 } 86 87 /// <summary> 88 /// 创建时间 89 /// </summary> 90 public DateTime CreateTime { get; set; } 91 92 /// <summary> 93 /// 创建人 94 /// </summary> 95 public string Creator { get; set; } 96 97 /// <summary> 98 /// 最后修改时间 99 /// </summary> 100 public DateTime LastModifyTime { get; set; } 101 102 /// <summary> 103 /// 最后修改人 104 /// </summary> 105 public string LastModifier { get; set; } 106 107 /// <summary> 108 /// 相等性比较 109 /// </summary> 110 /// <param name="other">要比较的对象</param> 111 /// <returns>true 相等 false 不相等</returns> 112 public override bool Equals(object other) 113 { 114 if (ReferenceEquals(null, other)) return false; 115 if (ReferenceEquals(this, other)) return true; 116 if (other.GetType() != this.GetType()) return false; 117 118 return Equals((FlowControlEvent)other); 119 } 120 121 /// <summary> 122 /// 流控事件是否等于同一类型的另一个流控事件 123 /// </summary> 124 /// <param name="other">同一类型的另一个流控事件</param> 125 /// <returns>true 相等 false 不相等</returns> 126 public bool Equals(FlowControlEvent other) 127 { 128 if (other == null) 129 return false; 130 if (!string.Equals(this.ID , other.ID) || this.IsEnable != other.IsEnable || this.Duration!= other.Duration 131 || !string.Equals(this.StrategyName, other.StrategyName)||this.TriggerTime!= other.TriggerTime) 132 return false; 133 134 return true; 135 } 136 137 /// <summary> 138 /// 重载GetHashCode方法 139 /// </summary> 140 /// <returns>HashCode</returns> 141 public override int GetHashCode() 142 { 143 unchecked 144 { 145 var result = 0; 146 result = (result * 397) ^ ID.GetHashCode(); 147 result = (result * 397) ^ IsEnable.GetHashCode(); 148 result = (result * 397) ^ Duration.GetHashCode(); 149 result = (result * 397) ^ StrategyName.GetHashCode(); 150 result = (result * 397) ^ TriggerTime.GetHashCode(); 151 return result; 152 } 153 } 154 }
周国庆
2017/4/25