1.简单发送Get请求

/// <summary>
/// 指定Url地址使用Get 方式获取全部字符串
/// </summary>
/// <param name="url">请求链接地址</param>
/// <returns></returns>
public static string Get(string url)
{
    string result = "";
    HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
    //清除缓存
    HttpRequestCachePolicy noCachePolicy = new HttpRequestCachePolicy(HttpRequestCacheLevel.NoCacheNoStore);
    req.CachePolicy = noCachePolicy;
    HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
    Stream stream = resp.GetResponseStream();
    try
    {
        //获取内容
        using (StreamReader reader = new StreamReader(stream))
        {
            result = reader.ReadToEnd();
        }
    }
    finally
    {
        stream.Close();
    }
    return result;
}

2.带请求参数的Get方法

/// <summary>
/// 发送Get请求
/// </summary>
/// <param name="url">地址</param>
/// <param name="dic">请求参数定义</param>
/// <returns></returns>
public static string Get(string url, Dictionary<string, string> dic)
{
    string result = "";
    StringBuilder builder = new StringBuilder();
    builder.Append(url);
    if (dic.Count > 0)
    {
        builder.Append("?");
        int i = 0;
        foreach (var item in dic)
        {
            if (i > 0)
                builder.Append("&");
            builder.AppendFormat("{0}={1}", item.Key, item.Value);
            i++;
        }
    }
    HttpWebRequest req = (HttpWebRequest)WebRequest.Create(builder.ToString());
    //添加参数
    HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
    Stream stream = resp.GetResponseStream();
    try
    {
        //获取内容
        using (StreamReader reader = new StreamReader(stream))
        {
            result = reader.ReadToEnd();
        }
    }
    finally
    {
        stream.Close();
    }
    return result;
}

3.自定义指定Http请求头，自定义指定编码解析返回结果

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
req.Method = "GET";
req.Headers["Accept-Language"] = "zh-CN,zh;q=0.8";
req.Referer = "https://www.baidu.com/";
HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
Stream stream = resp.GetResponseStream();
string result = "";
//注意，此处使用的编码是：gb2312
//using (StreamReader reader = new StreamReader(stream, Encoding.Default))
using (StreamReader reader = new StreamReader(stream, Encoding.GetEncoding("gb2312")))
{
    result = reader.ReadToEnd();
}