封装一个给 .NET Framework 用的内存缓存帮助类

news2024/9/20 16:54:28

前言

.NET Core 中已经内置了内存缓存相关的类和操作方法，直接就能使用，非常方便。但在 .NET Framework 中，如果想要使用内存缓存，需要自己进行封装。本文分享一个我自己项目中封装的内存缓存帮助类，有需要的童鞋可以拿去根据自己的实际业务修改修改，应用到自己的项目中。

代码

封装内存缓存类 CacheUtil

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);
	}
  }
}

使用

// 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);