创建REST服务应用程序

Web服务类别有两种，一种是基于SOAP协议的服务，另一种是基于HTTP协议的REST架构风格的服务。REST服务的数据格式有两种：XML 和 JSON，REST服务已被大量应用于移动互联网中。

本文将简要介绍创建一个REST服务应用程序以及使用它（仅仅是个示例，没有做代码优化）。

一、创建REST服务

1.新建一个空的解决方案，添加“WCF服务应用程序”

2.添加一个服务契约接口：IStudentService.cs，代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.ServiceModel;
using System.Runtime.Serialization;

namespace RESTService
{
    /// <summary>
    /// 服务契约：对学生信息进行增删改查
    /// </summary>
    [ServiceContract]
    public interface IStudentService
    {
        [OperationContract]
        string GetStuName(string id);

        [OperationContract]
        Student GetStu(string id);

        [OperationContract]
        bool UpdateStuAge(Student stu);

        [OperationContract]
        bool AddStu(Student stu);

        [OperationContract]
        bool DeleteStu(Student stu);
    }

    /// <summary>
    /// 数据契约
    /// </summary>
    [DataContract]
    public class Student
    {
        [DataMember]
        public string ID { get; set; }

        [DataMember]
        public string Name { get; set; }

        [DataMember]
        public int Age { get; set; }
    }
}

3.添加REST服务：StudentService.svc，如图：

该服务类实现上述服务契约接口，代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Activation;
using System.ServiceModel.Web;
using System.Text;

namespace RESTService
{
    [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single)]
    [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
    public class StudentService : IStudentService
    {
        // 要使用 HTTP GET，请添加 [WebGet] 特性。(默认 ResponseFormat 为 WebMessageFormat.Json)
        // 要创建返回 XML 的操作，
        //     请添加 [WebGet(ResponseFormat=WebMessageFormat.Xml)]，
        //     并在操作正文中包括以下行:
        //         WebOperationContext.Current.OutgoingResponse.ContentType = "text/xml";


        private static List<Student> _listStu;

        public StudentService()
        {
            _listStu = new List<Student> 
            {
                new Student{ID="1",Name="Jim",Age=24},
                new Student{ID="2",Name="Tom",Age=23}
            };
        }

        [WebGet(UriTemplate = "REST/GetName/{id}", ResponseFormat = WebMessageFormat.Json)]
        public string GetStuName(string id)
        {
            Student stu = this.GetStu(id);
            if (stu == null)
            {
                return "不存在此学生！";
            }
            else
            {
                return stu.Name;
            }
        }

        [WebGet(UriTemplate = "REST/Get/{id}", ResponseFormat = WebMessageFormat.Json)]
        public Student GetStu(string id)
        {
            Student stu = _listStu.Find(s => s.ID == id);
            return stu;
        }


        [WebInvoke(UriTemplate = "REST/Update/", Method = "POST", ResponseFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.Bare)]
        public bool UpdateStuAge(Student stu)
        {
            Student stu2 = this.GetStu(stu.ID);
            if (stu2 == null)
            {
                return false;
            }
            else
            {
                _listStu.Remove(stu2);
                _listStu.Add(stu);

                return true;
            }
        }

        [WebInvoke(UriTemplate = "REST/Add/", Method = "PUT", ResponseFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.Bare)]
        public bool AddStu(Student stu)
        {
            if (_listStu == null)
            {
                _listStu = new List<Student>();
            }

            _listStu.Add(stu);
            return true;
        }

        [WebInvoke(UriTemplate = "REST/Delete/", Method = "DELETE", ResponseFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.Bare)]
        public bool DeleteStu(Student stu)
        {
            Student stu2 = this.GetStu(stu.ID);
            if (stu2 == null)
            {
                return false;
            }
            else
            {
                _listStu.Remove(stu2);
                return true;
            }
        }
    }
}

关于WEB消息主体风格的介绍

4.WebConfig文件内容：

<?xml version="1.0" encoding="utf-8"?>
<configuration>

  <appSettings>
    <add key="aspnet:UseTaskFriendlySynchronizationContext" value="true" />
  </appSettings>
  <system.web>
    <compilation debug="true" targetFramework="4.5" />
    <httpRuntime targetFramework="4.5"/>
  </system.web>
  <system.serviceModel>
    <services>
      <service name="RESTService.StudentService">
        <endpoint address="" behaviorConfiguration="RESTService.StudentServiceAspNetAjaxBehavior"
          binding="webHttpBinding" contract="RESTService.IStudentService" />
      </service>
    </services>
    <behaviors>
      <endpointBehaviors>
        <behavior name="RESTService.StudentServiceAspNetAjaxBehavior">
          <!--<enableWebScript />-->
          <webHttp helpEnabled="true"/>
        </behavior>
      </endpointBehaviors>
      <serviceBehaviors>
        <behavior name="">
          <serviceMetadata httpGetEnabled="true" httpsGetEnabled="true" />
          <serviceDebug includeExceptionDetailInFaults="true" />
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <protocolMapping>
        <add binding="basicHttpsBinding" scheme="https" />
    </protocolMapping>    
    <serviceHostingEnvironment aspNetCompatibilityEnabled="true"
      multipleSiteBindingsEnabled="true" />
  </system.serviceModel>
  <system.webServer>
    <modules runAllManagedModulesForAllRequests="true"/>
    <!--
        若要在调试过程中浏览 Web 应用程序根目录，请将下面的值设置为 True。
        在部署之前将该值设置为 False 可避免泄露 Web 应用程序文件夹信息。
      -->
    <directoryBrowse enabled="true"/>
  </system.webServer>

</configuration>

5.在浏览器中查看REST服务信息

在浏览器地址栏的url后面输入help，即可查看该服务提供了哪些操作

二、调用REST服务

1.为了演示方便，本例采用WinForm应用程序调用REST服务（当然你也可以使用Android，IOS，IPad，WP等等其他客户端进行测试），界面效果如图：

2.后台代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Runtime.Serialization.Json;
using RESTService;
using System.IO;

namespace RESTClient
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        /// <summary>
        /// Json 反序列化
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="jsonString"></param>
        /// <returns></returns>
        public static T JsonDeserialize<T>(string jsonString)
        {
            DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(T));
            MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(jsonString));
            T obj = (T)serializer.ReadObject(ms);
            return obj;
        }

        /// <summary>
        /// Json 反序列化
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="ms"></param>
        /// <returns></returns>
        public static T JsonDeserialize<T>(Stream ms)
        {
            DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(T));
            T obj = (T)serializer.ReadObject(ms);
            return obj;
        }

        /// <summary>
        /// Json 序列化
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="t"></param>
        /// <returns></returns>
        public static string JsonSerializer<T>(T t)
        {
            DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(T));
            using (MemoryStream ms = new MemoryStream())
            {
                serializer.WriteObject(ms, t);
                return Encoding.UTF8.GetString(ms.ToArray());
            }
        }

        /// <summary>
        /// GET 操作
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnGet_Click(object sender, EventArgs e)
        {
            string uri = string.Format("http://localhost:4563/StudentService.svc/rest/get/{0}", this.txtID.Text.Trim());
            HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(uri);
            wr.Method = "GET";
            HttpWebResponse resp = (HttpWebResponse)wr.GetResponse();
            if (resp.ContentLength <= 0)
            {
                MessageBox.Show("不存在此学生！");
                this.txtID.Text = "";
                this.txtName.Text = "";
                this.txtAge.Text = "";
            }
            else
            {
                Stream ms = resp.GetResponseStream();
                Student stu = JsonDeserialize<Student>(ms);
                this.txtID.Text = stu.ID;
                this.txtName.Text = stu.Name;
                this.txtAge.Text = stu.Age.ToString();
            }
        }

        /// <summary>
        /// POST 操作
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnPost_Click(object sender, EventArgs e)
        {
            string uri = string.Format("http://localhost:4563/StudentService.svc/rest/update/");
            Student stu = new Student();
            stu.ID = this.txtID.Text.Trim();
            stu.Name = this.txtName.Text.Trim();
            stu.Age = Convert.ToInt32(this.txtAge.Text.Trim());
            byte[] bs = Encoding.UTF8.GetBytes(JsonSerializer<Student>(stu));
            HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(uri);
            wr.Method = "POST";
            wr.ContentLength = bs.Length;
            wr.ContentType = "application/json";
            using (Stream reqStream = wr.GetRequestStream())
            {
                reqStream.Write(bs, 0, bs.Length);
            }
            HttpWebResponse resp = (HttpWebResponse)wr.GetResponse();
            using (Stream respStream = resp.GetResponseStream())
            {
                StreamReader sr = new StreamReader(respStream);
                string result = sr.ReadToEnd();
                if (result == "true")
                {
                    MessageBox.Show("更新成功！");
                }
                else
                {
                    MessageBox.Show("更新失败！");
                }
            }
        }

        /// <summary>
        /// PUT 操作
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnPut_Click(object sender, EventArgs e)
        {
            string uri = string.Format("http://localhost:4563/StudentService.svc/rest/add/");
            Student stu = new Student();
            stu.ID = this.txtID.Text.Trim();
            stu.Name = this.txtName.Text.Trim();
            stu.Age = Convert.ToInt32(this.txtAge.Text.Trim());
            byte[] bs = Encoding.UTF8.GetBytes(JsonSerializer<Student>(stu));
            HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(uri);
            wr.Method = "PUT";
            wr.ContentLength = bs.Length;
            wr.ContentType = "application/json";
            using (Stream reqStream = wr.GetRequestStream())
            {
                reqStream.Write(bs, 0, bs.Length);
            }
            HttpWebResponse resp = (HttpWebResponse)wr.GetResponse();
            using (Stream respStream = resp.GetResponseStream())
            {
                StreamReader sr = new StreamReader(respStream);
                string result = sr.ReadToEnd();
                if (result == "true")
                {
                    MessageBox.Show("添加成功！");
                }
                else
                {
                    MessageBox.Show("添加失败！");
                }
            }
        }

        /// <summary>
        /// DELETE 操作
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnDelete_Click(object sender, EventArgs e)
        {
            string uri = string.Format("http://localhost:4563/StudentService.svc/rest/delete/");
            Student stu = new Student();
            stu.ID = this.txtID.Text.Trim();
            byte[] bs = Encoding.UTF8.GetBytes(JsonSerializer<Student>(stu));
            HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(uri);
            wr.Method = "DELETE";
            wr.ContentLength = bs.Length;
            wr.ContentType = "application/json";
            using (Stream reqStream = wr.GetRequestStream())
            {
                reqStream.Write(bs, 0, bs.Length);
            }
            HttpWebResponse resp = (HttpWebResponse)wr.GetResponse();
            using (Stream respStream = resp.GetResponseStream())
            {
                StreamReader sr = new StreamReader(respStream);
                string result = sr.ReadToEnd();
                if (result == "true")
                {
                    MessageBox.Show("删除成功！");
                }
                else
                {
                    MessageBox.Show("删除失败！");
                }
            }
        }
    }
}