c# http方法工具类整合

using System;
using System.IO;
using System.Net;
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Collections.Generic;

public class HttpUtil
{
    /// <summary>
    /// 通用http方法
    /// </summary>
    /// <param name="url">请求地址</param>
    /// <param name="postData">发送的数据</param>
    /// <param name="encoding">发送的编码格式</param>
    /// <param name="contentType">内容类型，取值推荐从本工具类的"HttpContentType"中取</param>
    /// <param name="postType">发送类型</param>
    /// <param name="headDic">头字典</param>
    /// <returns></returns>
    public static string HttpMethod(string url, string postData, Encoding encoding, string contentType, PostType postType, Dictionary<string, string> headDic)
    {
        try
        {
            if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase))
            {
                ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);
            }

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = postType.ToString();
            request.Accept = "*/*";
            request.ContentType = contentType;
            request.Credentials = CredentialCache.DefaultCredentials;
            //用户标识一定要加,不然有些严一点的网站会返回错误信息，比如说微信的，不按照规范来，很容易403
            request.UserAgent = "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; QQWubi 133; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; CIBA; InfoPath.2)";

            //添加请求头
            if (headDic != null && headDic.Count > 0)
            {
                Dictionary<string, string>.Enumerator it = headDic.GetEnumerator();
                while (it.MoveNext())
                {
                    request.Headers.Add(it.Current.Key, it.Current.Value);
                }
            }

            if (!string.IsNullOrEmpty(postData))
            {
                byte[] buffer = encoding.GetBytes(postData);
                request.ContentLength = buffer.Length;
                request.GetRequestStream().Write(buffer, 0, buffer.Length);
            }

            HttpWebResponse response;
            try
            {
                response = (HttpWebResponse)request.GetResponse();
                using (StreamReader reader = new StreamReader(response.GetResponseStream(), encoding))
                {
                    return reader.ReadToEnd();
                }
            }
            catch (WebException ex)
            {
                //这一步很有必要，因为有的地方会把错误信息放在异常里面，但是直接ex.message是看不到具体信息的，只有显示403拒绝访问
                response = (HttpWebResponse)ex.Response;
                using (StreamReader reader = new StreamReader(response.GetResponseStream(), encoding))
                {
                    return reader.ReadToEnd();
                }
            }
        }
        catch (Exception ex)
        {
            return ex.Message;//返回错误信息
        }
    }

    /// <summary>
    /// 请求类型
    /// </summary>
    public enum PostType
    {
        POST,
        GET
    }

    /// <summary>
    /// HTTP 内容类型(Content-Type)
    /// </summary>
    public class HttpContentType
    {
        /// <summary>
        /// 资源类型：普通文本
        /// </summary>
        public const string TEXT_PLAIN = "text/plain";

        /// <summary>
        /// 资源类型：JSON字符串
        /// </summary>
        public const string APPLICATION_JSON = "application/json";

        /// <summary>
        /// 资源类型：未知类型(数据流)
        /// </summary>
        public const string APPLICATION_OCTET_STREAM = "application/octet-stream";

        /// <summary>
        /// 资源类型：表单数据(键值对)
        /// </summary>
        public const string WWW_FORM_URLENCODED = "application/x-www-form-urlencoded";

        /// <summary>
        /// 资源类型：表单数据(键值对)。编码方式为 gb2312
        /// </summary>
        public const string WWW_FORM_URLENCODED_GB2312 = "application/x-www-form-urlencoded;charset=gb2312";

        /// <summary>
        /// 资源类型：表单数据(键值对)。编码方式为 utf-8
        /// </summary>
        public const string WWW_FORM_URLENCODED_UTF8 = "application/x-www-form-urlencoded;charset=utf-8";

        /// <summary>
        /// 资源类型：多分部数据
        /// </summary>
        public const string MULTIPART_FORM_DATA = "multipart/form-data";
    }

    private static bool CheckValidationResult(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
    {
        return true; //总是接受
    }
}