MVC项目实践,在三层架构下实现SportsStore-09,ASP.NET MVC调用ASP.NET Web API的查询 ...

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ASP.NET Web API和WCF都体现了REST软件架构风格。在REST中，把一切数据视为资源，所以也是一种面向资源的架构风格。所有的资源都可以通过URI来唯一标识，通过对资源的HTTP操作(GET/HEAD、POST、PUT和DELETE),使资源的表征状态发生了改变，即Representational State Transfer，缩写为REST。

WCF从3.5以来，也体现了REST的架构风格，但对于一般的消息通信来说，显得"过重"，所以，微软推出ASP.NET Web API，提供一种"轻量级"的服务，并且借鉴了MVC，以Controller的形式来定义服务，而Controller中的Action方法对应着不同的HTTP操作。

本篇为"在三层架构下实现SportsStore"系列的第九篇，包括：

■ 11、ASP.NET MVC调用ASP.NET Web API的增删改查服务
    □ 11.1 调用查询服务
        ※ 11.1.1 创建ASP.NET Web API项目引入Ninject
        ※ 11.1.2 提供ASP.NET WEB API增删改查服务
        ※ 11.1.3 ASP.NET MVC调用ASP.NET WEB API查询服务

11、ASP.NET MVC调用ASP.NET Web API提供增删改查服务

11.1 调用查询服务

System; using System.Collections.Generic; using System.Web.Http.Dependencies; using Ninject; namespace MySportsStore.WebApi.Extension { public class NinjectDependencyResolver : IDependencyResolver { private List<IDisposable> disposableServices = new List<IDisposable>(); public IKernel Kernel { get; private set; } public NinjectDependencyResolver(NinjectDependencyResolver parent) { this.Kernel = parent.Kernel; } public NinjectDependencyResolver() { this.Kernel = new StandardKernel(); } public void Register<TFrom, TTO>() where TTO : TFrom { this.Kernel.Bind<TFrom>().To<TTO>(); } public IDependencyScope BeginScope() { return new NinjectDependencyResolver(this); } public object GetService(System.Type serviceType) { return this.Kernel.TryGet(serviceType); } public System.Collections.Generic.IEnumerable<object> GetServices(System.Type serviceType) { foreach (var service in this.Kernel.GetAll(serviceType)) { this.AddDisposableService(service); yield return service; } } public void Dispose() { foreach (IDisposable disposable in disposableServices) { disposable.Dispose(); } } private void AddDisposableService(object service) { IDisposable disposable = service as IDisposable; if (null != disposable && !disposableServices.Contains(disposable)) { disposableServices.Add(disposable); } } } }

然后在全局中注册：

using System.Web.Http;
using MySportsStore.BLL;
using MySportsStore.IBLL;
using MySportsStore.WebApi.Extension;

namespace MySportsStore.WebApi
{
    public class WebApiApplication : System.Web.HttpApplication
    {
        protected void Application_Start()
        {
            GlobalConfiguration.Configure(WebApiConfig.Register);

            NinjectDependencyResolver dependencyResolver = new NinjectDependencyResolver();
            dependencyResolver.Register<IProductService, ProductService>();
            GlobalConfiguration.Configuration.DependencyResolver = dependencyResolver;
        }
    }
}

11.1.2 提供ASP.NET WEB API增删改查服务

在"MySportsStore.WebApi"下，创建ProductApi控制器，提供增删改查服务，实现如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web.Http;
using MySportsStore.IBLL;
using MySportsStore.Model;
using Ninject;

namespace MySportsStore.WebApi.Controllers
{
    public class ProductApiController : ApiController
    {
        [Inject]
        public IProductService ProductService { get; set; }

        public ProductApiController()
        {
            this.DisposableObjects = new List<IDisposable>();
            this.AddDisposableObject(ProductService);
        }

        // GET api/productapi
        public IEnumerable<Product> Get()
        {
            return ProductService.LoadEntities(p => true).AsEnumerable();
        }

        // GET api/productapi/5
        public Product Get(int id)
        {
            return ProductService.LoadEntities(p => p.Id == id).FirstOrDefault();
        }

        // POST api/productapi
        public void Post(Product product)
        {
            var dbProduct = ProductService.LoadEntities(p => p.Id == product.Id).FirstOrDefault();
            ProductService.UpdateEntity(dbProduct);
        }

        // PUT api/productapi/5
        public void Put(Product product)
        {
            ProductService.AddEntity(product);
        }

        // DELETE api/productapi/5
        public void Delete(int id)
        {
            var product = ProductService.LoadEntities(p => p.Id == id).FirstOrDefault();
            ProductService.DeleteEntity(product);
        }

        #region 手动垃圾回收逻辑
        protected IList<IDisposable> DisposableObjects { get; private set; }

        protected void AddDisposableObject(object obj)
        {
            IDisposable disposable = obj as IDisposable;
            if (disposable != null)
            {
                this.DisposableObjects.Add(disposable);
            }
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                foreach (IDisposable obj in this.DisposableObjects)
                {
                    if (null != obj)
                    {
                        obj.Dispose();
                    }
                }
            }
            base.Dispose(disposing);
        } 
        #endregion
    }
}

以上，通过Ninject把IProductService注入到ProductService属性上,然后使用ProductService实现增删改查，并实现了手动垃圾回收。

把"MySportsStore.WebApi"设置为启动项目，在浏览器输入：http://localhost:1577/api/productapi

以上，说明AP.NET WEB API查询数据服务是正常的。这里的地址，也就是代表查询状态的唯一URI，通过这个URI，无论你使用何种语言，无论是通过手机客户端、平板客户端、电脑客户端......你都可以调用这个REST风格的服务。

11.1.3 ASP.NET MVC调用ASP.NET WEB API查询服务

在MVC中，使用HttpClient来获取ASP.NET WEB API的服务，以下通过异步方式查询来自ASP.NET WEB API的数据：

using System.Collections.Generic;
using System.Net.Http;
using System.Threading.Tasks;
using MySportsStore.Model;
using Newtonsoft.Json;

namespace MySportsStore.WebUI.RESTServices
{
    public class ProductRESTService
    {
        readonly string uri = "http://localhost:1577/api/productapi";

        public async Task<List<Product>> GetProductsAsync()
        {
            using (HttpClient httpClient = new HttpClient())
            {
                return JsonConvert.DeserializeObject<List<Product>>(
                    await httpClient.GetStringAsync(uri)
                );
            }
        } 
    }
}

在"MySportsStore.WebUI"下，创建Home控制器：

using System.Threading.Tasks;
using System.Web.Mvc;
using MySportsStore.WebUI.RESTServices;

namespace MySportsStore.WebUI.Controllers
{
    public class HomeController : Controller
    {
        private ProductRESTService service = new ProductRESTService();

        public async Task<ActionResult> Index()
        {
            return View("Index",
                await service.GetProductsAsync()
            );
        }

    }
}

在"MySportsStore.WebUI"下，创建Home/Index.cshtml视图：

@model IEnumerable<MySportsStore.Model.Product>
@{
    Layout = null;
}

<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
    <script src="~/Scripts/jquery-1.8.2.js"></script>
    <style type="text/css">
        table {
            width: 1000px;
            border: 1px solid #000000;
            background-color: #eee;
        }

        table tr {
            line-height: 20px;
            border-bottom: 1px solid black;
        }

        table th {
            background-color: #ccc;
            color: #fff;
        }

        .oddRow {
            background-color: #fff;
        }

        #products {
            border: 0px solid red;
        }
    </style>
</head>
<body>
    <div id="products">
        <table>
            <tr class="oddRow">
                <th>编号</th>
                <th>类别</th>
                <th>名称</th>
                <th>价格</th>
                <th>描述</th>
            </tr>
            @foreach (var product in Model)
            {
                <tr>
                    <td>@product.Id</td>
                    <td>@product.Category</td>
                    <td>@product.Name</td>
                    <td>@product.Price.ToString("c")</td>
                    <td>@product.Description</td>
                </tr>
            }
        </table>
    </div>
</body>
</html>