using System;
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using System.Collections;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text.RegularExpressions;
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using System.Web;
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using System.Web.Caching;
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namespace ExportMap.cs
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{
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/// <summary>
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/// 缓存常用操作
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/// </summary>
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public class CacheUtils
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{
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public static CacheItemRemovedReason reason;
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public CacheUtils()
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{
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}
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/// <summary>
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/// 增加一个缓存对象
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/// </summary>
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/// <param name="strKey">键值名称</param>
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/// <param name="valueObj">被缓存对象</param>
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/// <param name="durationMin">缓存失效时间，默认为3分钟</param>
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/// <param name="priority">保留优先级(枚举数值)，1最不会被清除，6最容易被内存管理清除,0为default
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/// 【1:NotRemovable；2:High；3:AboveNormal；4:Normal；5:BelowNormal；6:Low】</param>
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/// <returns>缓存写入是否成功true 、 false</returns>
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public static bool InsertCach(string strKey, object valueObj, int durationMin, int priority)
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{
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TimeSpan ts;
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if (strKey != null && strKey.Length != 0 && valueObj != null)
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{
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//建立回调委托的一个实例
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//onRemove是委托执行的函数，具体方法看下面的onRemove(...)
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CacheItemRemovedCallback callBack = new CacheItemRemovedCallback(onRemove);
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#region 失效时间设置
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if (durationMin == 0)
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{
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ts = new TimeSpan(0, 30, 0);//如果不进行设置则为三分钟
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}
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else
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{
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ts = new TimeSpan(0, durationMin, 0);
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}
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#endregion
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#region System.Web.Caching.Cache 对象中存储的项的相对优先级
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CacheItemPriority cachePriority;
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switch (priority)
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{
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case 6:
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cachePriority = CacheItemPriority.Low;
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break;
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case 5:
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cachePriority = CacheItemPriority.BelowNormal;
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break;
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case 4:
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cachePriority = CacheItemPriority.Normal;
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break;
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case 3:
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cachePriority = CacheItemPriority.AboveNormal;
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break;
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case 2:
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cachePriority = CacheItemPriority.High;
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break;
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case 1:
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cachePriority = CacheItemPriority.NotRemovable;
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break;
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default:
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cachePriority = CacheItemPriority.Default;
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break;
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}
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#endregion
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HttpContext.Current.Cache.Insert(strKey, valueObj, null, DateTime.Now.Add(ts), Cache.NoSlidingExpiration, cachePriority, callBack);
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return true;
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}
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else
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{
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return false;
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}
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}
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/// <summary>
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/// 判断缓存对象是否存在
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/// </summary>
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/// <param name="strKey">缓存键值名称</param>
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/// <returns>是否存在true 、false</returns>
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public static bool IsExist(string strKey)
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{
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return HttpContext.Current.Cache[strKey] != null;
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}
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/// <summary>
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/// 读取缓存对象
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/// </summary>
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/// <param name="strKey">缓存键值名称</param>
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/// <returns>缓存对象，objec类型</returns>
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public static object GetCache(string strKey)
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{
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//取出值
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if (HttpContext.Current.Cache[strKey] != null)
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{
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object obj = HttpContext.Current.Cache[strKey];
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if (obj == null)
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{
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return null;
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}
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else
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{
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return obj;
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}
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}
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else
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{
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return null;
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}
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}
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/// <summary>
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/// 删除缓存对象
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/// </summary>
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/// <param name="strKey">缓存键值名称</param>
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public static void Remove(string strKey)
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{
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if (HttpContext.Current.Cache[strKey] != null)
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{
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HttpContext.Current.Cache.Remove(strKey);
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}
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}
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/// <summary>
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/// 根据设置的正则表达式清除缓存对象；
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/// 该方法使用正则匹配要删除的键值对象，如果键值命名统一规范，可批处理清除相关缓存数据O(∩_∩)O
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/// </summary>
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/// <param name="pattern">匹配键值的正则表达式</param>
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public static void RemoveByRegexp(string pattern)
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{
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if (pattern != "")
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{
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IDictionaryEnumerator enu = HttpContext.Current.Cache.GetEnumerator();
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while (enu.MoveNext())
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{
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string key = enu.Key.ToString();
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if (Regex.IsMatch(key, pattern))
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{
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Remove(key);
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}
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}
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}
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}
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/// <summary>
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/// 清除所有缓存对象
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/// </summary>
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public static void Clear()
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{
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IDictionaryEnumerator enu = HttpContext.Current.Cache.GetEnumerator();
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while (enu.MoveNext())
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{
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Remove(enu.Key.ToString());
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}
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}
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/// <summary>
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/// 此方法在值失效之前调用，可以用于在失效之前更新数据库，或从数据库重新获取数据
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/// </summary>
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/// <param name="strKey"></param>
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/// <param name="obj"></param>
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/// <param name="reason"></param>
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private static void onRemove(string strKey, object obj, CacheItemRemovedReason r)
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{
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reason = r;
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}
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}
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}
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