HttpContext.Current.Cache 和 HttpRuntime.Cache 对象区别

HttpContext.Current.Cache 和 HttpRuntime.Cache 对象区别

.NET中Cache有两种调用方式：HttpContext.Current.Cache 和 HttpRuntime.Cache，这两种方式有什么区别呢？我们先看MSDN上的解释：
HttpContext.Current.Cache：为当前 HTTP 请求获取Cache对象。
HttpRuntime.Cache：获取当前应用程序的Cache。

我们再用.NET Reflector工具看看HttpContext.Cache和HttpRuntime.Cache的实现：

//System.Web.HttpContext.Cache属性实现
public sealed class HttpContext

//System.Web.HttpRuntime.Cache属性实现
public sealed class HttpRuntime
class CacheTest
{
static void Main(string[] args)
{
System.Web.Caching.Cache httpRuntimeCache = System.Web.HttpRuntime.Cache;
httpRuntimeCache.Insert("httpRuntimeCache", "I am stored in HttpRuntime.Cache");

if (httpRuntimeCache != null)
{
Console.WriteLine("httpRuntimeCache:" + httpRuntimeCache["httpRuntimeCache"]);
}

System.Web.HttpContext httpContext = System.Web.HttpContext.Current;
if (httpContext == null)
{
Console.WriteLine("HttpContext object is null in Console Project");
}
else
{
System.Web.Caching.Cache httpContextCache = httpContext.Cache;
httpContextCache.Insert("httpContextCache", "I am stored in HttpRuntime.Cache");
if (httpContextCache == null)
{
Console.WriteLine("httpContextCache is null");
}
}

Console.ReadLine();
}
}
复制代码

输出结果：httpRuntimeCache:I am stored in HttpRuntime.Cache
HttpContext object is null in Console Project

综上：我们在使用Cache时，尽量使用HttpRuntime.Cache，既能减少出错，也减少了一次函数调用。