nugt包依赖：
- 1.Microsoft.Extensions.Caching.Abstractions
- 2.Microsoft.Extensions.Caching.Memory
封装的帮助类
添加类库Snblog.Cache
新建文件 Cache
新建帮助类 CacheManager.cs
using Microsoft.Extensions.Caching.Memory;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Reflection;
using System.Text;
namespace Snblog.Cache.Cache
{
public class CacheManager
{
public static CacheManager Default = new CacheManager();
public TimeSpan time = new TimeSpan(00, 00, 01, 0); //缓存过期时间
private IMemoryCache _cache = new MemoryCache(new MemoryCacheOptions());
/// <summary>
/// 判断是否在缓存中
/// </summary>
/// <param name="key">关键字</param>
/// <returns></returns>
public bool IsInCache(string key)
{
List<string> keys = GetAllKeys();
foreach (var i in keys)
{
if (i == key) return true;
}
return false;
}
/// <summary>
/// 获取所有缓存键
/// </summary>
/// <returns></returns>
public List<string> GetAllKeys()
{
const BindingFlags flags = BindingFlags.Instance | BindingFlags.NonPublic;
var entries = _cache.GetType().GetField("_entries", flags).GetValue(_cache);
var cacheItems = entries as IDictionary;
var keys = new List<string>();
if (cacheItems == null) return keys;
foreach (DictionaryEntry cacheItem in cacheItems)
{
keys.Add(cacheItem.Key.ToString());
}
return keys;
}
/// <summary>
/// 获取所有的缓存值
/// </summary>
/// <returns></returns>
public List<T> GetAllValues<T>()
{
var cacheKeys = GetAllKeys();
List<T> vals = new List<T>();
cacheKeys.ForEach(i =>
{
T t;
if (_cache.TryGetValue<T>(i, out t))
{
vals.Add(t);
}
});
return vals;
}
/// <summary>
/// 取得缓存数据
/// </summary>
/// <typeparam name="T">类型值</typeparam>
/// <param name="key">关键字</param>
/// <returns></returns>
public T Get<T>(string key)
{
if (string.IsNullOrWhiteSpace(key))
throw new ArgumentNullException(nameof(key));
T value;
_cache.TryGetValue<T>(key, out value);
return value;
}
/// <summary>
/// 设置缓存(永不过期)
/// </summary>
/// <param name="key">关键字</param>
/// <param name="value">缓存值</param>
public void Set_NotExpire<T>(string key, T value)
{
if (string.IsNullOrWhiteSpace(key))
throw new ArgumentNullException(nameof(key));
T v;
if (_cache.TryGetValue(key, out v))
_cache.Remove(key);
_cache.Set(key, value);
}
/// <summary>
/// 设置缓存(滑动过期:超过一段时间不访问就会过期,一直访问就一直不过期)
/// </summary>
/// <param name="key">关键字</param>
/// <param name="value">缓存值</param>
public void Set_SlidingExpire<T>(string key, T value, TimeSpan span)
{
if (string.IsNullOrWhiteSpace(key))
throw new ArgumentNullException(nameof(key));
T v;
if (_cache.TryGetValue(key, out v))
_cache.Remove(key);
_cache.Set(key, value, new MemoryCacheEntryOptions()
{
SlidingExpiration = span
});
}
/// <summary>
/// 设置缓存(绝对时间过期:从缓存开始持续指定的时间段后就过期,无论有没有持续的访问)
/// </summary>
/// <param name="key">关键字</param>
/// <param name="value">缓存值</param>
public void Set_AbsoluteExpire<T>(string key, T value, TimeSpan span)
{
if (string.IsNullOrWhiteSpace(key))
throw new ArgumentNullException(nameof(key));
T v;
if (_cache.TryGetValue(key, out v))
_cache.Remove(key);
_cache.Set(key, value, span);
}
/// <summary>
/// 设置缓存(绝对时间过期+滑动过期:比如滑动过期设置半小时,绝对过期时间设置2个小时，那么缓存开始后只要半小时内没有访问就会立马过期,如果半小时内有访问就会向后顺延半小时，但最多只能缓存2个小时)
/// </summary>
/// <param name="key">关键字</param>
/// <param name="value">缓存值</param>
/// <param name="slidingSpan"></param>
/// <param name="absoluteSpan"></param>
public void Set_SlidingAndAbsoluteExpire<T>(string key, T value, TimeSpan slidingSpan, TimeSpan absoluteSpan)
{
if (string.IsNullOrWhiteSpace(key))
throw new ArgumentNullException(nameof(key));
T v;
if (_cache.TryGetValue(key, out v))
_cache.Remove(key);
_cache.Set(key, value, new MemoryCacheEntryOptions()
{
SlidingExpiration = slidingSpan,
AbsoluteExpiration = DateTimeOffset.Now.AddMilliseconds(absoluteSpan.Milliseconds)
});
}
/// <summary>
/// 移除缓存
/// </summary>
/// <param name="key">关键字</param>
public void Remove(string key)
{
if (string.IsNullOrWhiteSpace(key))
throw new ArgumentNullException(nameof(key));
_cache.Remove(key);
}
/// <summary>
/// 释放
/// </summary>
public void Dispose()
{
if (_cache != null)
_cache.Dispose();
GC.SuppressFinalize(this);
}
}
}
Service中使用
//创建内存缓存对象
private static CacheManager _cache = new CacheManager();
/// <summary>
/// 返回总条数
/// </summary>
/// <returns></returns>
public int GetArticleCount()
{
int result;
if (_cache.IsInCache("GetArticleCount")) //是否存在缓存
{
result = _cache.Get<int>("GetArticleCount");//读缓存值
if (result <= 0)
{
_cache.Set_AbsoluteExpire("GetArticleCount", CreateService<SnArticle>().Count(), _cache.time);//设置缓存
result = _cache.Get<int>("GetArticleCount");
}
}
else
{
_cache.Set_AbsoluteExpire("GetArticleCount", CreateService<SnArticle>().Count(), _cache.time); //设置缓存
result = _cache.Get<int>("GetArticleCount");
}
return result;
}