MVC缓存01,使用控制器缓存或数据层缓存

2023-08-08 10:01:10

对一些浏览频次多、数据量大的数据，使用缓存会比较好，而对一些浏览频次低，或内容因用户不同的，不太适合使用缓存。

在控制器层面，MVC为我们提供了OutputCacheAttribute特性；在数据层使用缓存，用System.Runtime.Caching是不错的选择。

控制器层面使用OutputCacheAttribute缓存

□ OutputCacheAttribute默认的缓存时间是60秒。

[OutputCache(Duration=20, VaryByParam="none")]

public ActionResult Index()

 ViewBag.Message = DateTime.Now.ToString();

 return View();

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□ 设置缓存位置

缓存的位置通过OutputCacheLocation这个枚举来设置，默认的缓存位置是OutputCacheLocation.Any。OutputCacheLocation其它枚举项包括：Client,Downstream, Server, None, or ServerAndClient。如果我们想把一个与用户有关的信息保存在客户端：

[OutputCache(Duration = 7200, Location = OutputCacheLocation.Client, VaryByParam = "none", NoStore = true)]

public ActionResult Index()

 ViewBag.Message = "Welcome : " + User.Identity.Name;

 return View();

数据层缓存，通过System.Runtime.Caching

□ 创建一个叫Demo的数据库，并创建表Vehicle。

□ 从数据库生成一个"ADO.NET实体数据模型"CachingDemo.edmx

同时，自动生成了继承EF的DbContext的类DemoEntities：

并且，在配置文件中自动生成了EF相关内容和连接字符串：

□ 引入System.Runtime.Cache

□ 缓存接口

namespace MvcApplication1.Cache

    public interface ICacheProvider

        object Get(string key);

        void Set(string key, object data, int cacheTime);

        bool IsSet(string key);

        void Invalidate(string key);

□ 缓存实现

using System;

using System.Runtime.Caching;

namespace MvcApplication1.Cache

    public class DefaultCacheProvider : ICacheProvider

        private ObjectCache Cache

            get { return MemoryCache.Default; }

        public object Get(string key)

            return Cache[key];

        public void Set(string key, object data, int cacheTime)

            CacheItemPolicy policy = new CacheItemPolicy();

            policy.AbsoluteExpiration = DateTime.Now + TimeSpan.FromMinutes(cacheTime);

            Cache.Add(new CacheItem(key, data), policy);

        public bool IsSet(string key)

            return (Cache[key] != null);

        public void Invalidate(string key)

            Cache.Remove(key);

□ Vehicle的Repository接口：

using System.Collections.Generic;

using MvcApplication1.Models;

namespace MvcApplication1.Repository

    public interface IVehicleRepository

        void ClearCache();

        IEnumerable<Vehicle> GetVehicles();

□ Vehicle的Repository接口实现：

using System.Collections.Generic;

using System.Linq;

using MvcApplication1.Cache;

using MvcApplication1.Models;

namespace MvcApplication1.Repository

    public class VehicleRepository : IVehicleRepository

        protected DemoEntities DataContext { get; private set; }

        public ICacheProvider Cache { get; set; }

        public VehicleRepository() : this(new DefaultCacheProvider())

        public VehicleRepository(ICacheProvider cacheProvider)

            this.DataContext = new DemoEntities();

            this.Cache = cacheProvider;

        public void ClearCache()

            Cache.Invalidate("vehicles");

        public System.Collections.Generic.IEnumerable<Models.Vehicle> GetVehicles()

            IEnumerable<Vehicle> vehicles = Cache.Get("vehicles") as IEnumerable<Vehicle>;

            if (vehicles == null)

                vehicles = DataContext.Vehicle.OrderBy(v => v.Id).ToList();

                if (vehicles.Any())

                    Cache.Set("vehicles",vehicles,30); //设置缓存的时间为30分钟

            return vehicles;

□ HomeController

using System.Web.Mvc;

using MvcApplication1.Repository;

namespace MvcApplication1.Controllers

    public class HomeController : Controller

        public IVehicleRepository Repository { get; set; }

        public HomeController(IVehicleRepository repository)

            this.Repository = repository;

        public HomeController() : this(new VehicleRepository())

        public ActionResult Index()

            return View(Repository.GetVehicles());

        [HttpPost]

        public ActionResult Index(FormCollection form)

            Repository.ClearCache();

            return RedirectToAction("Index");

□ Home/Index.cshtml

@model IEnumerable<MvcApplication1.Models.Vehicle>

@{

    ViewBag.Title = "Index";

    Layout = "~/Views/Shared/_Layout.cshtml";

<style type="text/css">

    table td {

        border-collapse: collapse;

        border: solid 1px black;

</style>

<table cellpadding="0" cellspacing="0" border="0">

    <tr>

        <th>编号</th>

        <th>车型</th>

        <th>价格</th>

    </tr>

    @foreach (var vehicle in Model)

        <tr>

            <td>@vehicle.Id.ToString()</td>

            <td>@vehicle.Name</td>

            <td>@string.Format("{0:c}",vehicle.Price)</td>

        </tr>

</table>

@using (Html.BeginForm())

    <input type="submit" value="使缓存失效重新获取数据库数据" id="InvalidButton" name="InvalidButton"/>

□ 结果

页面第一次加载：

在数据库改变数据，页面内容不变：

点击按钮使缓存失效，视图显示数据库最新数据：

总结

当在数据层使用System.Runtime.Caching，实际上，所有的缓存操作都围绕MemoryCache.Default返回类型为ObjectCache缓存而进行。

□ 参考资料

※ Understanding Caching in Asp.Net MVC with example

※ DATA CACHING WITH .NET 4.0 AND ASP.NET MVC – PART 1

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