众所周知, ASP.NET的System.Web命名空间下的缓存可以用来保存一段时间的数据
因此, 在项目中我们可能利用它来保存一些缓存数据.
因此, 很多人写了这样的工具类来保存和加载缓存
保存缓存:
public
static
void SetCache(
string CacheKey,
object objObject)
{
System.Web.Caching.Cache objCache = HttpRuntime.Cache;
objCache.Insert(key, objObject);
}
{
System.Web.Caching.Cache objCache = HttpRuntime.Cache;
objCache.Insert(key, objObject);
}
public
static
void SetCache(
string CacheKey,
object objObject, DateTime absoluteExpiration, TimeSpan slidingExpiration)
{
System.Web.Caching.Cache objCache = HttpRuntime.Cache;
objCache.Insert(key, objObject, null, absoluteExpiration, slidingExpiration);
}
{
System.Web.Caching.Cache objCache = HttpRuntime.Cache;
objCache.Insert(key, objObject, null, absoluteExpiration, slidingExpiration);
}
加载缓存:
public
static
object GetCache(
string CacheKey)
{
System.Web.Caching.Cache objCache = HttpRuntime.Cache;
return objCache[key];
}
{
System.Web.Caching.Cache objCache = HttpRuntime.Cache;
return objCache[key];
}
但是这样就引入了一个问题:
如果多个用户同时访问,缓存是不是会被覆盖呢,或者同一个用户打开不同的窗口,缓存是否会被覆盖呢?
经过测试,答案是肯定的.
那么,如何解决这个问题呢?
我们想到了sessionId, 那个是一个用户的会话的概念.
因此,我们只要引入一个工具类,用来获取用户的会话id
public static string GetSessionId()
{
return HttpContext.Current.Session.SessionID;
}
修改后的代码如下
保存缓存:
public
static
void SetCache(
string CacheKey,
object objObject)
{
System.Web.Caching.Cache objCache = HttpRuntime.Cache;
string sessionId = Utility.GetSessionId();
string key = CacheKey + " _ " + sessionId;
objCache.Insert(key, objObject);
}
{
System.Web.Caching.Cache objCache = HttpRuntime.Cache;
string sessionId = Utility.GetSessionId();
string key = CacheKey + " _ " + sessionId;
objCache.Insert(key, objObject);
}
public static void SetCache(string CacheKey, object objObject, DateTime absoluteExpiration, TimeSpan slidingExpiration)
{
System.Web.Caching.Cache objCache = HttpRuntime.Cache;
string sessionId = Utility.GetSessionId();
string key = CacheKey + "_" + sessionId;
objCache.Insert(key, objObject, null, absoluteExpiration, slidingExpiration);
}
{
System.Web.Caching.Cache objCache = HttpRuntime.Cache;
string sessionId = Utility.GetSessionId();
string key = CacheKey + "_" + sessionId;
objCache.Insert(key, objObject, null, absoluteExpiration, slidingExpiration);
}
加载缓存:
public
static
object GetCache(
string CacheKey)
{
System.Web.Caching.Cache objCache = HttpRuntime.Cache;
string sessionId = Utility.GetSessionId();
string key = CacheKey + " _ " + sessionId;
return objCache[key];
}
{
System.Web.Caching.Cache objCache = HttpRuntime.Cache;
string sessionId = Utility.GetSessionId();
string key = CacheKey + " _ " + sessionId;
return objCache[key];
}
经过测试, 问题解决OK
