本文通过IDistributedCache的接口方法，实现Redis与MemoryCache统一帮助类。只需要在配置文件中简单的配置一下，就可以实现Redis与MemoryCache的切换。

IDistributedCache

IDistributedCache 方法：

IDistributedCache 还提供了一些扩展方法，本文的帮助类就是通过扩展方法完成的。

IDistributedCache 扩展方法：

ICache 接口

ICache接口提供了设置缓存、获取缓存、删除缓存和刷新缓存的接口方法。

  namespace CacheHelper {     public interface ICache     {         #region 设置缓存          /// <summary>         /// 设置缓存         /// </summary>         /// <param name="key">缓存Key</param>         /// <param name="value">值</param>         void SetCache(string key, object value);         /// <summary>         /// 设置缓存         /// </summary>         /// <param name="key">缓存Key</param>         /// <param name="value">值</param>         Task SetCacheAsync(string key, object value);          /// <summary>         /// 设置缓存         /// 注：默认过期类型为绝对过期         /// </summary>         /// <param name="key">缓存Key</param>         /// <param name="value">值</param>         /// <param name="timeout">过期时间间隔</param>         void SetCache(string key, object value, TimeSpan timeout);          /// <summary>         /// 设置缓存         /// 注：默认过期类型为绝对过期         /// </summary>         /// <param name="key">缓存Key</param>         /// <param name="value">值</param>         /// <param name="timeout">过期时间间隔</param>         Task SetCacheAsync(string key, object value, TimeSpan timeout);          /// <summary>         /// 设置缓存         /// 注：默认过期类型为绝对过期         /// </summary>         /// <param name="key">缓存Key</param>         /// <param name="value">值</param>         /// <param name="timeout">过期时间间隔</param>         /// <param name="expireType">过期类型</param>           void SetCache(string key, object value, TimeSpan timeout, ExpireType expireType);          /// <summary>         /// 设置缓存         /// 注：默认过期类型为绝对过期         /// </summary>         /// <param name="key">缓存Key</param>         /// <param name="value">值</param>         /// <param name="timeout">过期时间间隔</param>         /// <param name="expireType">过期类型</param>           Task SetCacheAsync(string key, object value, TimeSpan timeout, ExpireType expireType);         #endregion          #region 获取缓存          /// <summary>         /// 获取缓存         /// </summary>         /// <param name="key">缓存Key</param>         string GetCache(string key);          /// <summary>         /// 获取缓存         /// </summary>         /// <param name="key">缓存Key</param>         Task<string> GetCacheAsync(string key);         /// <summary>         /// 获取缓存         /// </summary>         /// <param name="key">缓存Key</param>         T GetCache<T>(string key);         /// <summary>         /// 获取缓存         /// </summary>         /// <param name="key">缓存Key</param>         Task<T> GetCacheAsync<T>(string key);          #endregion          #region 删除缓存          /// <summary>         /// 清除缓存         /// </summary>         /// <param name="key">缓存Key</param>         void RemoveCache(string key);          /// <summary>         /// 清除缓存         /// </summary>         /// <param name="key">缓存Key</param>         Task RemoveCacheAsync(string key);          #endregion          #region 刷新缓存         /// <summary>         /// 刷新缓存         /// </summary>         /// <param name="key">缓存Key</param>         void RefreshCache(string key);         /// <summary>         /// 刷新缓存         /// </summary>         /// <param name="key">缓存Key</param>         Task RefreshCacheAsync(string key);         #endregion     } }  

ExpireType枚举

ExpireType枚举标识缓存的过期类型，分为绝对过期与相对过期两个类型。
绝对过期：即自创建一段时间后就过期
相对过期：即该键未被访问后一段时间后过期，若此键一直被访问则过期时间自动延长。

namespace CacheHelper {     public enum ExpireType     {         /// <summary>         /// 绝对过期         /// 注：即自创建一段时间后就过期         /// </summary>         Absolute,          /// <summary>         /// 相对过期         /// 注：即该键未被访问后一段时间后过期，若此键一直被访问则过期时间自动延长         /// </summary>         Relative,     } }  

CacheType 枚举

是使用MemoryCache，还是Redis，MemoryCache不支持分布式，Redis支持分布式。

namespace CacheHelper {     public enum CacheType     {         /// <summary>         /// 使用内存缓存(不支持分布式)         /// </summary>         Memory,          /// <summary>         /// 使用Redis缓存(支持分布式)         /// </summary>         Redis     } } 

CacheHelper 缓存帮助类

namespace CacheHelper {     public class CacheHelper : ICache     {         readonly IDistributedCache _cache;          public CacheHelper(IDistributedCache cache)         {             _cache = cache;         }          protected string BuildKey(string idKey)         {             return $"Cache_{GetType().FullName}_{idKey}";         }         public void SetCache(string key, object value)         {             string cacheKey = BuildKey(key);             _cache.SetString(cacheKey, value.ToJson());         }          public async Task SetCacheAsync(string key, object value)         {             string cacheKey = BuildKey(key);             await _cache.SetStringAsync(cacheKey, value.ToJson());         }          public void SetCache(string key, object value, TimeSpan timeout)         {             string cacheKey = BuildKey(key);             _cache.SetString(cacheKey, value.ToJson(), new DistributedCacheEntryOptions             {                 AbsoluteExpiration = new DateTimeOffset(DateTime.Now + timeout)             });         }          public async Task SetCacheAsync(string key, object value, TimeSpan timeout)         {             string cacheKey = BuildKey(key);             await _cache.SetStringAsync(cacheKey, value.ToJson(), new DistributedCacheEntryOptions             {                 AbsoluteExpiration = new DateTimeOffset(DateTime.Now + timeout)             });         }          public void SetCache(string key, object value, TimeSpan timeout, ExpireType expireType)         {             string cacheKey = BuildKey(key);             if (expireType == ExpireType.Absolute)             {                 //这里没转换标准时间，Linux时区会有问题？                 _cache.SetString(cacheKey, value.ToJson(), new DistributedCacheEntryOptions                 {                     AbsoluteExpiration = new DateTimeOffset(DateTime.Now + timeout)                 });             }             else             {                 _cache.SetString(cacheKey, value.ToJson(), new DistributedCacheEntryOptions                 {                     AbsoluteExpirationRelativeToNow = timeout                 });             }         }          public async Task SetCacheAsync(string key, object value, TimeSpan timeout, ExpireType expireType)         {             string cacheKey = BuildKey(key);             if (expireType == ExpireType.Absolute)             {                 //这里没转换标准时间，Linux时区会有问题？                 await _cache.SetStringAsync(cacheKey, value.ToJson(), new DistributedCacheEntryOptions                 {                     AbsoluteExpiration = new DateTimeOffset(DateTime.Now + timeout)                 });             }             else             {                 await _cache.SetStringAsync(cacheKey, value.ToJson(), new DistributedCacheEntryOptions                 {                     AbsoluteExpirationRelativeToNow = timeout                 });             }         }          public string GetCache(string idKey)         {             if (idKey.IsNullOrEmpty())             {                 return null;             }             string cacheKey = BuildKey(idKey);             var cache = _cache.GetString(cacheKey);             return cache;         }         public async Task<string> GetCacheAsync(string key)         {             if (key.IsNullOrEmpty())             {                 return null;             }             string cacheKey = BuildKey(key);             var cache = await _cache.GetStringAsync(cacheKey);             return cache;         }          public T GetCache<T>(string key)         {             var cache = GetCache(key);             if (!cache.IsNullOrEmpty())             {                 return cache.ToObject<T>();             }             return default(T);         }          public async Task<T> GetCacheAsync<T>(string key)         {             var cache = await GetCacheAsync(key);             if (!string.IsNullOrEmpty(cache))             {                 return cache.ToObject<T>();             }             return default(T);         }          public void RemoveCache(string key)         {             _cache.Remove(BuildKey(key));         }          public async Task RemoveCacheAsync(string key)         {             await _cache.RemoveAsync(BuildKey(key));         }          public void RefreshCache(string key)         {             _cache.Refresh(BuildKey(key));         }          public async Task RefreshCacheAsync(string key)         {             await _cache.RefreshAsync(BuildKey(key));         }      } }  

CacheHelper 中，自定义了一个string的扩展方法ToObject<T>()。ToObject<T>()扩展方法使用了 Newtonsoft.Json。

/// <summary> /// 将Json字符串反序列化为对象 /// </summary> /// <typeparam name="T">对象类型</typeparam> /// <param name="jsonStr">Json字符串</param> /// <returns></returns> public static T ToObject<T>(this string jsonStr) {     return JsonConvert.DeserializeObject<T>(jsonStr); } 

CacheHelper 的使用方法

安装Redis依赖

Redis依赖我使用的是Caching.CSRedis，安装依赖：

PM> Install-Package Caching.CSRedis -Version 3.6.90 

配置appsettings.json

在appsettings.json中，对缓存进行配置：

 "Cache": {     "CacheType": "Memory", // "Memory OR Redis"     "RedisEndpoint": "127.0.0.1:6379" //Redis节点地址,定义详见 https://github.com/2881099/csredis   }, 

如果要使用MemoryCache，CacheType就设置为Memory，如果要使用Redis，CacheType就设置为Redis。如果设置为Redis的话，还需要配置RedisEndpoint，保证Redis节点可用。

CacheOptions配置

编写一个名为CacheOptions的类。用于获取配置文件的配置节内容

namespace CacheHelper {     public class CacheOptions     {         public CacheType CacheType { get; set; }         public string RedisEndpoint { get; set; }     } } 

IHostBuilder扩展方法UseCache

编写一个IHostBuilder的扩展方法UseCache，用于注入MemoryCache或是Redis

public static IHostBuilder UseCache(this IHostBuilder hostBuilder) {     hostBuilder.ConfigureServices((buidlerContext, services) =>     {         var cacheOption = buidlerContext.Configuration.GetSection("Cache").Get<CacheOptions>();         switch (cacheOption.CacheType)         {             case CacheType.Memory: services.AddDistributedMemoryCache(); break;             case CacheType.Redis:                 {                     var csredis = new CSRedisClient(cacheOption.RedisEndpoint);                     RedisHelper.Initialization(csredis);                     services.AddSingleton(csredis);                     services.AddSingleton<IDistributedCache>(new CSRedisCache(RedisHelper.Instance));                 }; break;             default: throw new Exception("缓存类型无效");         }     });      return hostBuilder; } 

Program.cs中引用

var builder = WebApplication.CreateBuilder(args); builder.Host.UseCache(); 

CacheHelper的使用。

public class HomeController { 	readonly ICache _cache; 	public HomeController 	( 		ICache cache, 	) 	{ 		_cache = cache; 	} 	 	public async Task CacheTest(string key) 	{ 		string cache_value = "hello cache"; 		//同步方法 		_cache.SetCache(key,cache_value ); 		string v = _cache.GetCache<string>(key); 		_cache.RemoveCache(key); 		//异步方法 		await _cache.SetCacheAsync(key,cache_value ); 		string val = await _cache.GetCacheAsync<string>(key); 		await _cache.RemoveCacheAsync(key); 	} } 

总结

暂无，下次再会！