环境：ASP.NET Core MVC，Redis-Win-x64-3.2.100

本文介绍在ASP.NET Core MVC中怎么用Redis缓存数据。

1、启动Redis服务器，就是让我们的Redis跑起来，具体参照https://blog.csdn.net/u012835032/article/details/115438693。

2、要在ASP.NET Core MVC中用Redis需要做什么？参考https://blog.csdn.net/u012835032/article/details/115443710。

代码很简单，但开始前需要先了解两个要用到对象

DistributedCacheExtensions：包括对缓存操作的方法

#region 程序集 Microsoft.Extensions.Caching.Abstractions, Version=2.1.23.0, Culture=neutral, PublicKeyToken=adb9793829ddae60

using System.Runtime.CompilerServices;
using System.Threading;
using System.Threading.Tasks;

namespace Microsoft.Extensions.Caching.Distributed
{
    //
    // 摘要:
    //     Extension methods for setting data in an Microsoft.Extensions.Caching.Distributed.IDistributedCache.
    public static class DistributedCacheExtensions
    {
        //
        // 摘要:
        //     Gets a string from the specified cache with the specified key.
        //
        // 参数:
        //   cache:
        //     The cache in which to store the data.
        //
        //   key:
        //     The key to get the stored data for.
        //
        // 返回结果:
        //     The string value from the stored cache key.
        public static string GetString(this IDistributedCache cache, string key);
        //
        // 摘要:
        //     Asynchronously gets a string from the specified cache with the specified key.
        //
        // 参数:
        //   cache:
        //     The cache in which to store the data.
        //
        //   key:
        //     The key to get the stored data for.
        //
        //   token:
        //     Optional. A System.Threading.CancellationToken to cancel the operation.
        //
        // 返回结果:
        //     A task that gets the string value from the stored cache key.
        [AsyncStateMachine(typeof(<GetStringAsync>d__7))]
        public static Task<string> GetStringAsync(this IDistributedCache cache, string key, CancellationToken token = default(CancellationToken));
        //
        // 摘要:
        //     Sets a sequence of bytes in the specified cache with the specified key.
        //
        // 参数:
        //   cache:
        //     The cache in which to store the data.
        //
        //   key:
        //     The key to store the data in.
        //
        //   value:
        //     The data to store in the cache.
        //
        // 异常:
        //   T:System.ArgumentNullException:
        //     Thrown when key or value is null.
        public static void Set(this IDistributedCache cache, string key, byte[] value);
        //
        // 摘要:
        //     Asynchronously sets a sequence of bytes in the specified cache with the specified
        //     key.
        //
        // 参数:
        //   cache:
        //     The cache in which to store the data.
        //
        //   key:
        //     The key to store the data in.
        //
        //   value:
        //     The data to store in the cache.
        //
        //   token:
        //     Optional. A System.Threading.CancellationToken to cancel the operation.
        //
        // 返回结果:
        //     A task that represents the asynchronous set operation.
        //
        // 异常:
        //   T:System.ArgumentNullException:
        //     Thrown when key or value is null.
        public static Task SetAsync(this IDistributedCache cache, string key, byte[] value, CancellationToken token = default(CancellationToken));
        //
        // 摘要:
        //     Sets a string in the specified cache with the specified key.
        //
        // 参数:
        //   cache:
        //     The cache in which to store the data.
        //
        //   key:
        //     The key to store the data in.
        //
        //   value:
        //     The data to store in the cache.
        //
        // 异常:
        //   T:System.ArgumentNullException:
        //     Thrown when key or value is null.
        public static void SetString(this IDistributedCache cache, string key, string value);
        //
        // 摘要:
        //     Sets a string in the specified cache with the specified key.
        //
        // 参数:
        //   cache:
        //     The cache in which to store the data.
        //
        //   key:
        //     The key to store the data in.
        //
        //   value:
        //     The data to store in the cache.
        //
        //   options:
        //     The cache options for the entry.
        //
        // 异常:
        //   T:System.ArgumentNullException:
        //     Thrown when key or value is null.
        public static void SetString(this IDistributedCache cache, string key, string value, DistributedCacheEntryOptions options);
        //
        // 摘要:
        //     Asynchronously sets a string in the specified cache with the specified key.
        //
        // 参数:
        //   cache:
        //     The cache in which to store the data.
        //
        //   key:
        //     The key to store the data in.
        //
        //   value:
        //     The data to store in the cache.
        //
        //   token:
        //     Optional. A System.Threading.CancellationToken to cancel the operation.
        //
        // 返回结果:
        //     A task that represents the asynchronous set operation.
        //
        // 异常:
        //   T:System.ArgumentNullException:
        //     Thrown when key or value is null.
        public static Task SetStringAsync(this IDistributedCache cache, string key, string value, CancellationToken token = default(CancellationToken));
        //
        // 摘要:
        //     Asynchronously sets a string in the specified cache with the specified key.
        //
        // 参数:
        //   cache:
        //     The cache in which to store the data.
        //
        //   key:
        //     The key to store the data in.
        //
        //   value:
        //     The data to store in the cache.
        //
        //   options:
        //     The cache options for the entry.
        //
        //   token:
        //     Optional. A System.Threading.CancellationToken to cancel the operation.
        //
        // 返回结果:
        //     A task that represents the asynchronous set operation.
        //
        // 异常:
        //   T:System.ArgumentNullException:
        //     Thrown when key or value is null.
        public static Task SetStringAsync(this IDistributedCache cache, string key, string value, DistributedCacheEntryOptions options, CancellationToken token = default(CancellationToken));
    }
}

DistributedCacheEntryOptions：设置缓存有效期

#region 程序集 Microsoft.Extensions.Caching.Abstractions, Version=2.1.23.0, Culture=neutral, PublicKeyToken=adb9793829ddae60

using System;

namespace Microsoft.Extensions.Caching.Distributed
{
    public class DistributedCacheEntryOptions
    {
        public DistributedCacheEntryOptions();

        //
        // 摘要:
        //     Gets or sets an absolute expiration date for the cache entry.
        public DateTimeOffset? AbsoluteExpiration { get; set; }
        //
        // 摘要:
        //     Gets or sets an absolute expiration time, relative to now.
        public TimeSpan? AbsoluteExpirationRelativeToNow { get; set; }
        //
        // 摘要:
        //     Gets or sets how long a cache entry can be inactive (e.g. not accessed) before
        //     it will be removed. This will not extend the entry lifetime beyond the absolute
        //     expiration (if set).
        public TimeSpan? SlidingExpiration { get; set; }
    }
}

 使用要先在Startup.cs把分布式缓存（IDistributedCache）加进来，就是ASP.NET Core MVC的Ioc那套玩儿。

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddDistributedRedisCache(options =>
            {
                options.Configuration = "127.0.0.1:6379";
                options.InstanceName = "RedisTest";
            });
            //password
            //services.AddDistributedRedisCache(options =>
            //{
            //    options.Configuration = "127.0.0.1:6379,password=123456,defaultdatabase=1";
            //    options.InstanceName = "RedisTest_";
            //});


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

控制器代码如下，利用DistributedCacheExtensions提供的方法写入和获取数据。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Caching.Distributed;

namespace RedisTest
{
    public class HomeController : BaseController
    {
        private IDistributedCache DistributedCache;

        public HomeController(IDistributedCache distributedCache)
        {
            DistributedCache = distributedCache;
        }

        public IActionResult Index()
        {
            ViewBag.DistributedCacheDateTime = GetCacheDateTime();

            return View();
        }

        private string GetCacheDateTime()
        {
            string dCacheKey = "Home-GetCacheDateTime";
            //获取缓存数据
            string data = DistributedCache.GetString(dCacheKey);
            if (string.IsNullOrWhiteSpace(data))
            {
                data = DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss fff");
                //写入缓存，并指定缓存到期时间 300秒
                DistributedCache.SetString(dCacheKey, data, new DistributedCacheEntryOptions()
                {
                    AbsoluteExpirationRelativeToNow = TimeSpan.FromSeconds(300)
                });
            }
            return data;
        }
    }
}

可以在命令行通过keys命令看一下