.Net整合Json实现REST服务客户端的方法详解

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;

namespace psi.Common
{
 public class HttpClientUtil
 {
  // REST @GET 方法，根据泛型自动转换成实体，支持List<T> 
  public static T doGetMethodToObj<T>(string url)
  {
   HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
   request.Method = "get";
   request.ContentType = "application/json;charset=UTF-8";
   HttpWebResponse response = null;
   try
   {
    response = (HttpWebResponse)request.GetResponse();
   }
   catch (WebException e)
   {
    response = (HttpWebResponse)e.Response;
    return default(T);
   }
   string json = getResponseString(response);
   return JsonConvert.DeserializeObject<T>(json);
  }

  // 将 HttpWebResponse 返回结果转换成 string 
  private static string getResponseString(HttpWebResponse response)
  {
   string json = null;
   using (StreamReader reader = new StreamReader(response.GetResponseStream(), System.Text.Encoding.GetEncoding("UTF-8")))
   {
    json = reader.ReadToEnd();
   }
   return json;
  }

  // 获取异常信息 
  private static string getRestErrorMessage(HttpWebResponse errorResponse)
  {
   string errorhtml = getResponseString(errorResponse);
   string errorkey = "UnhandledException:";
   errorhtml = errorhtml.Substring(errorhtml.IndexOf(errorkey) + errorkey.Length);
   errorhtml = errorhtml.Substring(0, errorhtml.IndexOf("\n"));
   return errorhtml;
  }

  // REST @POST 方法 
  public static T doPostMethodToObj<T>(string url, string jsonBody)
  {
   HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
   request.Method = "post";
   request.ContentType = "application/json;charset=UTF-8";
   var stream = request.GetRequestStream();
   using (var writer = new StreamWriter(stream))
   {
    writer.Write(jsonBody);
    writer.Flush();
   }
   HttpWebResponse response = (HttpWebResponse)request.GetResponse();
   string json = getResponseString(response);
   return JsonConvert.DeserializeObject<T>(json);
  }

  // REST @PUT 方法 
  public static string doPutMethod(string url)
  {
   HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
   request.Method = "put";
   request.ContentType = "application/json;charset=UTF-8";
   HttpWebResponse response = (HttpWebResponse)request.GetResponse();
   using (StreamReader reader = new StreamReader(response.GetResponseStream(), System.Text.Encoding.GetEncoding("UTF-8")))
   {
    return reader.ReadToEnd();
   }
  }

  // REST @PUT 方法，带发送内容主体 
  public static T doPutMethodToObj<T>(string url, string jsonBody)
  {
   HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
   request.Method = "put";
   request.ContentType = "application/json;charset=UTF-8";
   request.Timeout = 30 * 1000;
   var stream = request.GetRequestStream();
   using (var writer = new StreamWriter(stream))
   {
    writer.Write(jsonBody);
    writer.Flush();
   }
   HttpWebResponse response = (HttpWebResponse)request.GetResponse();
   string json = getResponseString(response);
   return JsonConvert.DeserializeObject<T>(json);
  }

  // REST @DELETE 方法 
  public static bool doDeleteMethod(string url)
  {
   HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
   request.Method = "delete";
   request.ContentType = "application/json;charset=UTF-8";
   HttpWebResponse response = (HttpWebResponse)request.GetResponse();
   using (StreamReader reader = new StreamReader(response.GetResponseStream(), System.Text.Encoding.GetEncoding("UTF-8")))
   {
    string responseString = reader.ReadToEnd();
    if (responseString.Equals("1"))
    {
     return true;
    }
    return false;
   }
  } 
 }
}

/// <summary>
/// 取得升级服务端的url地址
/// </summary>
/// <returns></returns>
private String getServerUrl()
{
 String result = "";
 UpgraderClient upgraderClient = getUpgraderClient();
 if (upgraderClient != null)
 {
  result += "http://" + upgraderClient.serverIP +
   ":" + upgraderClient.serverPort +
   "/upgraderServer/service/upgrade.do";
 }
 return result;
}

/// <summary>
/// 测试与升级服务端的连接
/// </summary>
/// <returns></returns>
public bool testConnect()
{
 FileRequest fileReq = new FileRequest();
 fileReq.type = (int)RequestType.TEST_CONNECT;
 string jsonData = JsonConvert.SerializeObject(fileReq);
 FileResponse rep = null;
 try
 {
  rep = HttpClientUtil.doPostMethodToObj<FileResponse>(getServerUrl(), jsonData);
 } catch
 {
  throw new Exception("连接远程服务端失败！");
 }
 return rep.status == 200;
}