.NET Core使用缓存

1.MemoryCache 服务器端缓存
添加服务：services.AddMemoryCache();
使用：注入IMemoryCache _memoryCache；

var cityList = new List<City>();
            if (!_memoryCache.TryGetValue("cities", out test))
            {
                cityList = _cityServices.GetAll();
                var cacheEntryOptions = new MemoryCacheEntryOptions()
                    .SetSlidingExpiration(TimeSpan.FromMinutes(5))
                    .SetAbsoluteExpiration(TimeSpan.FromDays(1));

                //缓存清除之后调用回调
                //cacheEntryOptions.RegisterPostEvictionCallback();

                _memoryCache.Set("cities",cityList);
            }
            return cityList;

2.CacheTagHelper自己查
3.使用Redis；NuGet安装Microsoft.Extensions.Caching.Redis
StartUp.cs注册服务：

services.AddDistributedRedisCache(options=> {
                options.Configuration = "localhost";
                options.InstanceName = "redis-for-albums";
            });

4.使用，注入IDistributedCache distributedCache，代码

var cityList = new List<City>();
            var cityListBytes = _distributedCache.Get("cities");
            if (cityListBytes == null)
            {
                cityList = _cityServices.GetAll();
                var cityString = JsonConvert.SerializeObject(cityList);
                byte[] cityEncode = Encoding.UTF8.GetBytes(cityString);
                var cacheEntryOptions = new MemoryCacheEntryOptions()
                    .SetSlidingExpiration(TimeSpan.FromMinutes(5));
                _distributedCache.Set("cities", cityEncode);
            }
            else
            {
                byte[] cityEncode = _distributedCache.Get("cities");
                var cityString = Encoding.UTF8.GetString(cityEncode);
                cityList = JsonConvert.DeserializeObject<List<City>>(cityString);
            }
            return cityList;

5.ResponseCache，