ASP.NET Core中的Caching组件简介

services.AddMemoryCache();
services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);

        private IMemoryCache memoryCache;
        public HomeController( IMemoryCache _memoryCache)
        {
            memoryCache = _memoryCache;
        }

        public IActionResult Index()
        {
            string cacheKey = "key";
            string result;
            if (!memoryCache.TryGetValue(cacheKey, out result))
            {
                result = $"LineZero{DateTime.Now}";
                memoryCache.Set(cacheKey, result);
                //设置相对过期时间
                memoryCache.Set(cacheKey, result, new MemoryCacheEntryOptions()
                    .SetSlidingExpiration(TimeSpan.FromSeconds(10)));
                //设置绝对过期时间
                memoryCache.Set(cacheKey, result, new MemoryCacheEntryOptions()
                    .SetAbsoluteExpiration(TimeSpan.FromSeconds(10)));
                //删除缓存
                memoryCache.Remove(cacheKey);
                //设置缓存优先级（程序压力大时，会根据优先级自动回收）
                memoryCache.Set(cacheKey,result,new MemoryCacheEntryOptions() 
                    .SetPriority(CacheItemPriority.NeverRemove));
                //过期时缓存回调
                memoryCache.Set(cacheKey, result, new MemoryCacheEntryOptions()
                    .SetAbsoluteExpiration(TimeSpan.FromSeconds(60))
                    .RegisterPostEvictionCallback((key, value, reason, substate)
                    =>
                    {
                        nlog.Warn($"键{key}值{value}改变,因为{reason}");
                    }));
                //Token过期时，缓存回调
                var cts = new CancellationTokenSource();
                memoryCache.Set(cacheKey, result, new MemoryCacheEntryOptions()
                    .AddExpirationToken(new CancellationChangeToken(cts.Token))
                    .RegisterPostEvictionCallback((key, value, reason, substate)
                    =>
                    {
                        nlog.Warn($"键{key}值{value}改变,因为{reason}");
                    }));
            }
            ViewBag.Cache = result;
            return View();
        }

@{
    ViewData["Title"] = "Home Page";
}
<distributed-cache name="mycache" expires-after="TimeSpan.FromSeconds(10)">
    <p>缓存项10秒过期(expires-after绝对过期时间)</p>
</distributed-cache>
<distributed-cache name="mycachenew" expires-sliding="TimeSpan.FromSeconds(10)">
    <p>相对十秒(expires-sliding相对过期时间)</p>
    @DateTime.Now
</distributed-cache>
<div>@ViewBag.Cache</div>