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The author:(作者)delv
published in(发表于) 2014/1/24 9:09:08
C#提交数据到服务器并返回的处理_[Asp.Net教程]

C#提交数据到服务器并返回的处理_[Asp.Net教程]

1:利用System.Net.WebRequest的Create方法创建WebRequest对象:



System.Net.WebRequest ObjWebRequest =System.Net.WebRequest.Create(urlP);


异常类型:
NotSupportedException :requestUri 中指定的请求方案未注册。
ArgumentNullException :requestUri 为空引用（Visual Basic 中为 Nothing）。
SecurityException 调用方没有连接到请求的 URI 或请求重定向到的 URI 上的权限。

2:对请求进行预先身份验证,如果无明确的要求,此项可以空.



ObjWebRequest.Credentials = CredentialCache.DefaultCredentials;



如果需要按照特别的验证协议,需要强制转换成HttpWebRequest类型:


((HttpWebRequest)ObjWebRequest).UserAgent = "5DO8";



3:指明协议的类型:


ObjWebRequest.Method = "POST";



可以是POST方式和Get方式.

4:发送传输的数据长度(如果无显示传送,亦可发送),如果设置了此项,发送的数据必须恰好满足此值.



ObjWebRequest.ContentLength = Stringdata.ToCharArray().Length;



5:设置传入请求的 MIME 内容类型:



ObjWebRequest.ContentType="application/x-www-form-urlencoded";//Post
ObjWebRequest.ContentType="text/xml";//SOAP



6:使用GetRequestStream()方法获取发送的流的句柄:



System.IO.Stream dataStream = ObjWebRequest.GetRequestStream();



7:发送数据:


dataStream.Write (byteArray, 0, byteArray.Length);



注:byteArray是一个Byte数组,它的获取可以是:


byte[] byteArray = UTF8Encoding.GetBytes(dataP);



8:关闭Request流.



dataStream.Close ();


这是必须的,知道Close,服务器不会响应输出,还可以选择调用System.IO.Stream.Close()关闭流.

9:利用GetResponse()获取Response对象.


WebResponse Objresponse = ObjWebRequest.GetResponse();




9*:你可以获取返回给客户端的 HTTP 输出状态的字符串,默认是公共状态消息"OK"



//Console.WriteLine (((HttpWebResponse)Objresponse).StatusDescription);
if ( ((HttpWebResponse)Objresponse).StatusDescription != "OK"){
//..结束这一切
}




10:获取响应流的句柄:


Stream data = Objresponse.GetResponseStream



11:保存数据或者直接读出,例如直接输出到浏览器.



dataStream = ObjResponse.GetResponseStream ();

StreamReader r = new StreamReader(dataStream);
Response.Write(HttpUtility.HtmlEncode(r.ReadToEnd()));


或者使用StreamWriter对象保存:


Stream outStream =System.IO.File.Create( "Temp.data" );
byte []buffer = new byte[1024];
int l;
do{
l = dataStream.Read(buffer,0,buffer.Length);
if(l>0) outStream.Write(buffer,0,l);
} while(l>0);

outStream.Close();



此方式可以保存二进制数据.

12:关闭流.


Objresponse.Close();




例如发送Soap文件时候,可以创建XmlDocument对象,直接使用Save()即可:



XmlDocument doc = new XmlDocument();
doc.Load( System.Web.HttpContext.Current.Server.MapPath(@"~")+@"\" + xmlfile);
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(@"http://s:81/5do8/webs.asmx");

req.ContentType = "text/xml;charset=\"utf-8\"";
req.Accept = "text/xml";
req.Method = "POST";

Stream stm = req.GetRequestStream();
doc.Save(stm);
stm.Close();
WebResponse resp = req.GetResponse();
stm = resp.GetResponseStream();
StreamReader r = new StreamReader(stm);
Response.Write(HttpUtility.HtmlEncode(r.ReadToEnd()));



-1:利用ASP发送XMLHTTP对象:



Set xmlhttp = server.CreateObject("Msxml2.XMLHTTP")
xmlhttp.Open "POST",url,false
xmlhttp.setRequestHeader "Content-Type", "text/xml;charset=utf-8"
xmlhttp.setRequestHeader "HOST","s"
xmlhttp.setRequestHeader "Content-Length",LEN(SoapRequest)
xmlhttp.setRequestHeader "SOAPAction", "http://s"
xmlhttp.Send(SoapRequest)
Response.Write xmlhttp.Status&” ”
Response.Write xmlhttp.StatusText
Set xmlhttp = Nothing



获取的时候:




If xmlhttp.Status = 200 Then
Set xmlDOC =server.CreateObject("MSXML.DOMDocument")
xmlDOC.load(xmlhttp.responseXML)
xmlStr = xmlDOC.xml
Set xmlDOC=nothing
xmlStr = Replace(xmlStr,"<","<")
xmlStr = Replace(xmlStr,">",">")
Response.write xmlStr
Else
Response.Write xmlhttp.Status&" "
Response.Write xmlhttp.StatusText
End if
请求正确则给出完整响应，请求不正确（如账号，密码不对）响应的内容就会信息不完整.
取出响应里的数据，如下：
If xmlhttp.Status = 200 Then
Set xmlDOC = server.CreateObject("MSXML.DOMDocument")
xmlDOC.load(xmlhttp.responseXML)
Response.Write xmlDOC.documentElement.selectNodes("//LoginByAccountResult")(0).text
Set xmlDOC = nothing
Else
Response.Write xmlhttp.Status&" "
Response.Write xmlhttp.StatusText
End if
显示某节点各个属性和数据的FUNCTION：
Function showallnode(rootname,myxmlDOC)
if rootname<>"" then
set nodeobj=myxmlDOC.documentElement.selectSingleNode("//"&rootname&"")'当前结点对像
nodeAttributelen=myxmlDOC.documentElement.selectSingleNode("//"&rootname&"").attributes.length'当前结点属性数
returnstring=returnstring&"
节点名称："&rootname
if nodeobj.text<>"" then
returnstring=returnstring&"
节点的文本：("&nodeobj.text&")"
end if
returnstring=returnstring&"
{
"
if nodeAttributelen<>0 then
returnstring=returnstring&"
属性数有 "&nodeAttributelen&" 个,分别是："
end if
for i=0 to nodeAttributelen-1
returnstring=returnstring&"
  • "&nodeobj.attributes(i).Name&": "&nodeobj.getAttribute(nodeobj.attributes(i).Name)&"
    • "
    next
    if nodeobj.childNodes.Length<>0 then
    if nodeobj.hasChildNodes() and lcase(nodeobj.childNodes.item(0).nodeName)<>"#text" then'是否有子节点
    set childnodeobj=nodeobj.childNodes
    childnodelen=nodeobj.childNodes.Length
    returnstring=returnstring&"

    有 "&childnodelen&" 个子节点;
    分别是: "
    for i=0 to childnodelen-1
    returnstring=returnstring&"
  • "&childnodeobj.item(i).nodeName&"
    • "
    next
    end if
    end if
    returnstring=returnstring&"
    }
    "
    response.write returnstring
    set nodeobj=nothing
    end if
    End Function
    可以这样用：
    If xmlhttp.Status = 200 Then
    Set xmlDOC = server.CreateObject("MSXML.DOMDocument")
    xmlDOC.load(xmlhttp.responseXML)
    showallnode "LoginByAccountResponse",xmlDOC’调用SHOWALLNODE
    Set xmlDOC = nothing
    Else
    Response.Write xmlhttp.Status&" "
    Response.Write xmlhttp.StatusText
    End if

    POST:

    url = "http://s/"
    SoapRequest="username="&username&"&password="&password
    Set xmlhttp = server.CreateObject("Msxml2.XMLHTTP")
    xmlhttp.Open "POST",url,false
    xmlhttp.setRequestHeader "Content-Type", "application/x-www-form-urlencoded"’注意
    xmlhttp.setRequestHeader "HOST","
    "
    xmlhttp.setRequestHeader "Content-Length",LEN(SoapRequest)
    xmlhttp.Send(SoapRequest)

    Response.Write xmlhttp.Status&” ”
    Response.Write xmlhttp.StatusText
    Set xmlhttp = Nothing

    'POST
    If xmlhttp.Status = 200 Then
    Set xmlDOC = server.CreateObject("MSXML.DOMDocument")
    xmlDOC.load(xmlhttp.responseXML)
    showallnode "string",xmlDOC'调用SHOWALLNODE
    Set xmlDOC = nothing
    Else
    Response.Write xmlhttp.Status&" "
    Response.Write xmlhttp.StatusText
    End if





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