ASP.NET Core教程：ASP.NET Core中使用Redis緩存

一、前言

我們這裏以StackExchange.Redis爲例，講解如何在ASP.NET Core中如何使用Redis實現緩存。首先需要安裝Redis和RedisDesktopManager。RedisDesktopManager用來查看Redis緩存裏面的數據。如何安裝Redis這裏不在講述。

二、安裝StackExchange.Redis

在NuGet上安裝StackExchange.Redis，如下圖所示：

 安裝完成以後在依賴項裏面就可以看到：

三、添加配置

 在appsettings.json文件裏面添加Redis相關配置信息：

{
  "Logging": {
    "LogLevel": {
      "Default": "Warning"
    }
  },
  "AllowedHosts": "*",
  "Redis": {
    "Default": {
      "Connection": "127.0.0.1:6379",
      "InstanceName": "local",
      "DefaultDB": 8
    }
  }
}

四、Redis幫助類

 創建Redis幫助類，代碼如下：

using StackExchange.Redis;
using System;
using System.Collections.Concurrent;

namespace RedisDemo
{
    public class RedisHelper : IDisposable
    {
        //連接字符串
        private string _connectionString;
        //實例名稱
        private string _instanceName;
        //默認數據庫
        private int _defaultDB; 
        private ConcurrentDictionary<string, ConnectionMultiplexer> _connections;
        public RedisHelper(string connectionString, string instanceName, int defaultDB = 0)
        {
            _connectionString = connectionString;
            _instanceName = instanceName;
            _defaultDB = defaultDB;
            _connections = new ConcurrentDictionary<string, ConnectionMultiplexer>();
        }

        /// <summary>
        /// 獲取ConnectionMultiplexer
        /// </summary>
        /// <returns></returns>
        private ConnectionMultiplexer GetConnect()
        {
            return _connections.GetOrAdd(_instanceName, p => ConnectionMultiplexer.Connect(_connectionString));
        }

        /// <summary>
        /// 獲取數據庫
        /// </summary>
        /// <param name="configName"></param>
        /// <param name="db">默認爲0：優先代碼的db配置，其次config中的配置</param>
        /// <returns></returns>
        public IDatabase GetDatabase()
        {
            return GetConnect().GetDatabase(_defaultDB);
        }

        public IServer GetServer(string configName = null, int endPointsIndex = 0)
        {
            var confOption = ConfigurationOptions.Parse(_connectionString);
            return GetConnect().GetServer(confOption.EndPoints[endPointsIndex]);
        }

        public ISubscriber GetSubscriber(string configName = null)
        {
            return GetConnect().GetSubscriber();
        }

        public void Dispose()
        {
            if (_connections != null && _connections.Count > 0)
            {
                foreach (var item in _connections.Values)
                {
                    item.Close();
                }
            }
        }
    }
}

五、添加服務依賴項

 在Startup.cs類的ConfigureServices方法裏面添加服務注入：

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace RedisDemo
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            //redis緩存
            var section = Configuration.GetSection("Redis:Default");
            //連接字符串
            string _connectionString = section.GetSection("Connection").Value;
            //實例名稱
            string _instanceName = section.GetSection("InstanceName").Value;
            //默認數據庫 
            int _defaultDB = int.Parse(section.GetSection("DefaultDB").Value ?? "0");           
            services.AddSingleton(new RedisHelper(_connectionString, _instanceName, _defaultDB));
            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseMvc();
        }
    }
}

六、在控制器中使用

 新建一個控制器，然後通過構造函數注入：

using Microsoft.AspNetCore.Mvc;
using StackExchange.Redis;

namespace RedisDemo.Controllers
{
    [Route("api/redis")]
    [ApiController]
    public class RedisController : ControllerBase
    {
        private readonly IDatabase _redis;
        public RedisController(RedisHelper client)
        {
            _redis = client.GetDatabase();
        }

        [HttpGet]
        public string Get()
        {
            // 往Redis裏面存入數據
            _redis.StringSet("Name", "Tom");
            // 從Redis裏面取數據
            string name = _redis.StringGet("Name");
            return name;
        }
    }
}

七、測試

運行程序，使用Postman測試控制器：

然後通過RedisDesktopManager查看Redis裏面的數據，這裏使用的Db8數據庫：