HttpWebRequest的常见错误使用TcpClient可避免

有时使用httpwebrequest对象会出现错误，总结有三种：
1、system.net.webexception: 服务器提交了协议冲突. section=responsestatusline
2、system.net.webexception: 基础连接已经关闭: 连接被意外关闭。
3、system.net.protocolviolationexception: 无法发送具有此谓词类型的内容正文。
使用tcpclient对象搞定：

private string gethtmltcp(string url)
{
string strhtml = "";//用来保存获得的html代码
tcpclient clientsocket = new tcpclient();
uri uri = new uri(url);
clientsocket.connect(uri.host, uri.port);
stringbuilder requestheaders = new stringbuilder();//用来保存html协议头部信息
requestheaders.appendformat("{0} {1} http/1.1\r\n", "get", uri.pathandquery);
requestheaders.appendformat("connection:close\r\n");
requestheaders.appendformat("host:{0}\r\n", uri.host);
requestheaders.appendformat("accept:*/*\r\n");
requestheaders.appendformat("accept-language:zh-cn\r\n");
requestheaders.appendformat("user-agent:mozilla/4.0 (compatible; msie 6.0; windows nt 5.2; sv1; .net clr 1.1.4322; .net clr 2.0.50727)\r\n\r\n");
encoding encoding = encoding.default;
byte[] request = encoding.getbytes(requestheaders.tostring());
clientsocket.client.send(request);
//获取要保存的网络流
stream readstream = clientsocket.getstream();
streamreader sr = new streamreader(readstream, encoding.default);
strhtml = sr.readtoend();
readstream.close();
clientsocket.close();
return strhtml;
}

使用 httpwebrequest请求页面

///
/// 获取html源码
///
///
///
///
static string gethtml(string url, string param)
{
try
{
uri uri = new uri(url);
httpwebrequest myreq = (httpwebrequest)webrequest.create(uri);
myreq.headers.add("accept-encoding", "gzip,deflate");//sdch
byte[] bydata = encoding.default.getbytes(param);
myreq.method = "post";
myreq.contentlength = bydata.length;
stream reqstrem = myreq.getrequeststream();
reqstrem.write(bydata, 0, bydata.length);
reqstrem.close();
httpwebresponse result = (httpwebresponse)myreq.getresponse();
stream recstream = result.getresponsestream();
//如果是gzip方式则需要解压
recstream = new gzipstream(recstream, compressionmode.decompress);
streamreader redstream = new streamreader(recstream, system.text.encoding.default);
string strhtml = redstream.readtoend();
redstream.close();
recstream.close();
result.close();
return strhtml;
}
catch (exception)
{
return "";
}
}