HttpWebRequest的GET和POST方法

命名空间： System.Net，这是.NET创建者最初开发用于使用HTTP请求的标准类。使用HttpWebRequest可以让开发者控制请求/响应流程的各个方面，如 timeouts, cookies, headers, protocols。

GET请求就很简单易懂啦，如果需要传参，在URL末尾加上“？+参数名=参数值”即可，需要注意的是POST请求。

POST请求参数类型有多个，设置不正确会发生错误的，一般第三方接口都是以JSON交换数据，请求中的参数设置涉及到了Stream流的一些知识点

1	httpWebRequest.GetRequestStream().Write(bs, 0, bs.Length);

这一行的意思是将“bs”从Request的“0”位置中开始写入，长度为“bs.Length”，说白了就是把参数数据加入到请求数据中。

string url = "http://www.webxml.com.cn/WebServices/WeatherWS.asmx/";
string postMethod = "getSupportCityDataset";//方法名
string postDataName = "theRegionCode";//参数名
string postDataValue = "3118";//参数值

string recGetstr= HttpGet(url,postMethod,postDataName,postDataValue); //调用GET

string recPoststr= HttpPost(url,postMethod,postDataName,postDataValue);//调用POST

public string HttpGet(string Url, string postMethod,string postDataName, string postDataValue)
        {
            if (postMethod.Length>0)
            {
                Url += postMethod;
            }
            if (postDataName.Length>0)
            {
                Url += "?" + postDataName;
            }
            if (postDataValue.Length>0)
            {
                Url += "=" + postDataValue;
            }
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);
            request.Method = "GET";
            request.ContentType = "text/html;charset=UTF-8";
            request.Timeout = 10000;

            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            Stream myResponseStream = response.GetResponseStream();
            StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));
            string retString = myStreamReader.ReadToEnd();
            myStreamReader.Close();
            myResponseStream.Close();
            return retString;
        }

public string HttpPost(string url, string postMethod, string postDataName, string postDataValue)
        {
            if (postMethod.Length>0)
            {
                url += postMethod;
            }
            string data = postDataName + "=" + postDataValue;
            HttpWebRequest httpWebRequest = (HttpWebRequest)HttpWebRequest.Create(url);
            //字符串转换为字节码
            byte[] bs = Encoding.UTF8.GetBytes(data);
            
            httpWebRequest.ContentType = "application/x-www-form-urlencoded";
            //参数数据长度
            httpWebRequest.ContentLength = bs.Length;
            //设置请求类型
            httpWebRequest.Method = "POST";
            //设置超时时间
            httpWebRequest.Timeout = 20000;
            //将参数写入请求地址中
            httpWebRequest.GetRequestStream().Write(bs, 0, bs.Length);
            //发送请求
            HttpWebResponse httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();
            //读取返回数据
            StreamReader streamReader = new StreamReader(httpWebResponse.GetResponseStream(), Encoding.UTF8);
            string responseContent = streamReader.ReadToEnd();
            streamReader.Close();
            httpWebResponse.Close();
            httpWebRequest.Abort();
            return responseContent;
        }