HttpWebRequest用法

GET方法

static void Main(string[] args)
{
string url = "http://www.xxx.com/?param1=value1¶m2=value2";
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);

request.Method = "GET";
request.Headers["Accept-Language"] = "zh-Hans-CN,zh-Hans;q=0.5";
request.Headers["Accept-Encoding"] = "gzip, deflate";
/*
如果要获取Cookie
CookieContainer cookieContainer = new CookieContainer();
request.CookieContainer = cookieContainer;
*/

/* 获取返回的网页内容 */
{
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
/* 此时已通过request.GetResponse()发出请求 */
StreamReader responseStream = new StreamReader(response.GetResponseStream());
string text = responseStream.ReadToEnd();
}
Console.WriteLine(text);

request.Abort();
response.Close();
responseStream.Close();
}

POST方法

static void Main(string[] args)
{
string url = "http://www.xxx.com";
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
byte[] postdata = Encoding.UTF8.GetBytes("param1=value1¶m2=value2");

request.Method = "POST";
request.Headers["Accept-Language"] = "zh-Hans-CN,zh-Hans;q=0.5";
request.Headers["Accept-Encoding"] = "gzip, deflate";
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = postdata.Length;
/*
如果要获取Cookie
CookieContainer cookieContainer = new CookieContainer();
request.CookieContainer = cookieContainer;
*/

/* 发送POST请
4000
求 */
Stream requestStream = request.GetRequestStream();
requestStream.Write(postdata, 0, postdata.Length);
/* 此时已通过HttpWebRequest.GetRequestStream().Write(byte[] buffer, int count)方法发出请求 */

/* 获取返回的网页内容 */
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
StreamReader responseStream = new StreamReader(response.GetResponseStream());
string text = responseStream.ReadToEnd();

Console.WriteLine(text);

request.Abort();
response.Close();
responseStream.Close();
}

要重复发送请求时需要再次使用

(HttpWebRequest)WebRequest.Creat(Uri)

,重新创建请求实现重复发送.

如果网站使用了GZIP/Deflate压缩,HttpWebRequest会自动解压缩.

使用HTTP代理

static void Main(string[] args)
{
string url = "http://www.xxx.com/?param1=value1¶m2=value2";
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);

/* 创建并设置使用代理 */
WebProxy proxy = new WebProxy("127.0.0.1", 8888);
request.Proxy = proxy;

/*
如果HTTP代理需要账号密码登陆
proxy.Credentials = new NetworkCredential("UserName", "PassWord");
*/

/* 获取返回的网页内容 */
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
StreamReader responseStream = new StreamReader(response.GetResponseStream());
string text = responseStream.ReadToEnd();

Console.WriteLine(text);

request.Abort();
response.Close();
responseStream.Close();
}

CookieContainer中Cookie跨域或丢失问题

CookieContainer中已经有所需的Cookie时,使用HttpWebRequest发送请求却没有或缺少Cookies时的两个解决方案.

Here is the solution:

1. 不使用

CookieContainer.Add(Cookie)

方法,只使用

CookieContainer.Add(Uri, Cookie)

方法.

2. Call BugFix_CookieDomain each time you add a cookie to the container or before you use .GetCookie or before system use the container.

private void BugFix_CookieDomain(CookieContainer cookieContainer)
{
System.Type _ContainerType = typeof(CookieContainer);
Hashtable table = (Hashtable)_ContainerType.InvokeMember("m_domainTable",
System.Reflection.BindingFlags.NonPublic |
System.Reflection.BindingFlags.GetField |
System.Reflection.BindingFlags.Instance,
null,
cookieContainer,
new object[] { });
ArrayList keys = new ArrayList(table.Keys);
foreach (string keyObj in keys)
{
string key = (keyObj as string);
if (key[0] == '.')
{
string newKey = key.Remove(0, 1);
table[newKey] = table[keyObj];
}
}
}

来源:http://stackoverflow.com/a/1537490/6341466

实在搞不定就把Cookie发送就把得到的Cookie转为字符串赋值到HttpWebRequest.Headers[“Cookie”]中.