封装一个给 .NET Framework 用的内存缓存帮助类

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.Caching;
using System.Text;
using System.Threading.Tasks;
namespace Common.Util
{
  public static class CacheUtil
  {
  /// <summary>
  /// <para>获取预定的缓存的过期时间</para>
  /// <para>单位：小时</para>
  /// </summary>
  /// <returns></returns>
  public static int GetCacheExpirationTime()
  {
    // 默认过期时间是 2 小时
    int expiration = 2;
    
    // 从外部获取预定的缓存过期时间，如果有值，则将默认的过期时间改为外部设置的过期时间
    string cacheFile = Path.Combine(FileUtil.GetAppHomeBinPath(), "CacheExpiration.txt");
    Logger.DebugFormat("The cache expiration setting file is [{0}]", cacheFile);
    if (File.Exists(cacheFile))
    {
    using (StreamReader sr = new StreamReader(new FileStream(cacheFile, FileMode.Open, FileAccess.Read)))
    {
      var readBody = sr.ReadToEnd();
      int outExpiration = CommonUtil.GetObjTranNull<int>(readBody);
      if (outExpiration > 0) expiration = outExpiration;
    }
    }
    Logger.DebugFormat("The cache expiration setting is [{0}] hours", expiration);
    return expiration;
  }
  /// <summary>
  /// Set cache
  /// </summary>
  /// <param name="key"></param>
  /// <param name="obj"></param>
  /// <param name="expiration"></param>
  public static void Set(string key, object obj, int expiration)
  {
    var cache = MemoryCache.Default;
    var policy = new CacheItemPolicy
    {
    AbsoluteExpiration = DateTime.Now.AddHours(expiration)
    };
    cache.Set(key, obj, policy);
  }
  /// <summary>
  /// Get cach value by key
  /// </summary>
  /// <typeparam name="T"></typeparam>
  /// <param name="key"></param>
  /// <returns></returns>
  public static T Get<T>(string key)
  {
    try
    {
    var cache = MemoryCache.Default;
    var cacheVal = cache[key];
    return CommonUtil.GetObjTranNull<T>(cacheVal);
    }
    catch (Exception ex)
    {
    BDNALog.BDNALogger.DEFAULT.Warn("Error occurred when getting cache value: ", ex);
    return default(T);
    }
  }
  /// <summary>
  /// Check whether the cache item is exists by key
  /// </summary>
  /// <param name="key"></param>
  /// <returns></returns>
  public static bool IsKeyExists(string key)
  {
    var cache = MemoryCache.Default;
    return cache.Contains(key);
  }
  }
}

// 1. 判断缓存在不在
if (!CacheUtil.IsKeyExists("isNonInteractiveUser"))
{
  
}
// 2. 获取缓存的值
string val = CacheUtil.Get<string>("isNonInteractiveUser");
// 3. 设置缓存的值
bool isNonInteractiveUser = true;
int expiration = CacheUtil.GetCacheExpirationTime();
CacheUtil.Set("isNonInteractiveUser", isNonInteractiveUser, expiration);