Shulou(Shulou.com)06/01 Report--

最近编码的过程中，使用了对象本地内存缓存，缓存用了Dictionary, ConcurrentDictionary,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

htt p s : / / ms d n . mi c r o s o f t . c o m /en-us/library/ms131190(v=vs.110).aspx

2.重写bool Equals(object other)方法和 int GetHashCode()方法

htt p : / / s ta ck o v e r f l o w . co m / q u es t i o n s /2 7 3 49 1 4/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 /// 2 /// 流控事件 3 /// 4 [Serializable] 5 public class FlowControlEvent: IEquatable 6 { 7 public static readonly string Global = "Global"; 8 9 /// 10 /// 标识 11 /// 12 public string ID { get; set; } 13 14 /// 15 /// 流控策略名称 16 /// 17 public string StrategyName { get; set; } 18 19 /// 20 /// 是否手工触发 21 /// 22 public bool IsManuelTrigger { get; set; } 23 24 /// 25 /// 触发时间 26 /// 27 public DateTime TriggerTime { get; set; } 28 29 /// 30 /// 流控策略 31 /// 32 public FlowControlStrategy Strategy { get; set; } 33 34 /// 35 /// 持续时间，单位s 36 /// 37 public long Duration { get; set; } 38 39 //是否启用 40 private bool isEnable = true; 41 42 /// 43 /// 是否启用 44 /// 45 public bool IsEnable 46 { 47 get 48 { 49 return isEnable; 50 } 51 set 52 { 53 isEnable = value; 54 } 55 } 56 57 /// 58 /// 是否使用中 59 /// 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 /// 88 /// 创建时间 89 /// 90 public DateTime CreateTime { get; set; } 91 92 /// 93 /// 创建人 94 /// 95 public string Creator { get; set; } 96 97 /// 98 /// 最后修改时间 99 /// 100 public DateTime LastModifyTime { get; set; }101 102 /// 103 /// 最后修改人104 /// 105 public string LastModifier { get; set; }106 107 /// 108 /// 相等性比较109 /// 110 /// 要比较的对象111 /// true 相等 false 不相等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 /// 122 /// 流控事件是否等于同一类型的另一个流控事件123 /// 124 /// 同一类型的另一个流控事件125 /// true 相等 false 不相等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.Duration131 || !string.Equals(this.StrategyName, other.StrategyName)||this.TriggerTime!= other.TriggerTime)132 return false;133 134 return true;135 }136 137 /// 138 /// 重载GetHashCode方法139 /// 140 /// HashCode141 public override int GetHashCode()142 {143 unchecked144 {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 }

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