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導讀網絡技術是從1990年代中期發展起來的新技術，它把互聯網上分散的資源融為有機整體，實現資源的全面共享和有機協作，使人們能夠透明地使用資源的整體能力并按需獲取信息。資源包括高性能計算機、存儲資源、數據... 網絡技術是從1990年代中期發展起來的新技術，它把互聯網上分散的資源融為有機整體，實現資源的全面共享和有機協作，使人們能夠透明地使用資源的整體能力并按需獲取信息。資源包括高性能計算機、存儲資源、數據資源、信息資源、知識資源、專家資源、大型數據庫、網絡、傳感器等。 當前的互聯網只限于信息共享，網絡則被認為是互聯網發展的第三階段。 利用HttpRequest利用HttpRequest登錄到某個網站，然后獲取網站信息的程序示例 問題：有的網站的相關內容必須要在登錄后才可以查看，其登錄信息保存在session變量之中。這樣，使用asphttp等組件就難以正確得到所要的信息。解決：使用asp.net中的httprequest和httpresponse來實現。要點： 1。 通過附加一個cookiecontainer到httprequest對象中，可以得到登錄后返回的代表SESSION ID的COOKIE。 見Login方法 2。 將此COOKIE包含在一個cookiecontainer中并附加到另一個HTTPREQUEST請求中，則可以實現SESSION的還原。見getPage方法源程序如下：getHttpInfo.aspx: <%@ Page language="c#" Codebehind="getHttpInfo.aspx.cs" AutoEventWireup="false" Inherits="PdfTest.getHttpInfo" %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" > <HTML> <HEAD> <title>WebForm1</title> <meta content="Microsoft Visual Studio 7.0" name="GENERATOR"> <meta content="C#" name="CODE_LANGUAGE"> <meta content="javascript" name="vs_defaultClientscript"> <meta content="http://schemas.microsoft.com/intellisense/ie5"; name="vs_targetSchema"> </HEAD> <body> <form id="Form1" method="post" runat="server"> </form> </body> </HTML> getHttpInfo.aspx.cs: using System; using System.Collections; using System.ComponentModel; using System.Data; //using System.Data.OleDb; using System.Drawing; using System.Web; using System.Web.SessionState; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.HtmlControls; using System.Net; using System.IO; using System.Text; using System.Text.RegularExpressions; using Microsoft.Data.Odbc;namespace PdfTest { /// <summary> /// Summary description for WebForm1. /// </summary> public class getHttpInfo : System.Web.UI.Page { protected static string cookieheader; private void Page_Load(object sender, System.EventArgs e) { // Put user code to initialize the page herestring strResult;if (HttpContext.Current.Application["cookieheader"] != null) { cookieheader = (string)HttpContext.Current.Application["cookieheader"]; } else { //Login into the website and keep the cookie for the session in the application variable string strLogin = Login("http://www.thesiteyouwanttovisit/theloginpage.asp";, "Action=&USERID=&Password=") ; } strResult = getPage("http://www.thesiteyouwanttovisit/theloginpage.asp";, "Action=&data=") ; //Write the result to htm file FileStream htmFile = new FileStream("c:\save.htm", FileMode.OpenOrCreate); StreamWriter sw = new StreamWriter(htmFile); sw.Write(strResult); sw.Close(); htmFile.Close();// output the result Response.Write(strResult); } public static string Login(String url, String paramList) { HttpWebResponse res = null; string strResult="";try {HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url); req.Method = "POST"; req.ContentType = "application/x-www-form-urlencoded"; req.AllowAutoRedirect = false; CookieContainer cookieCon = new CookieContainer(); req.CookieContainer = cookieCon;StringBuilder UrlEncoded = new StringBuilder(); Char[] reserved = {?, =, &}; byte[] SomeBytes = null;if (paramList != null) { int i=0, j; while(i<paramList.Length) { j=paramList.IndexOfAny(reserved, i); if (j==-1) { UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, paramList.Length-i))); break; } UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, j-i))); UrlEncoded.Append(paramList.Substring(j,1)); i = j+1; } SomeBytes = Encoding.UTF8.GetBytes(UrlEncoded.ToString()); req.ContentLength = SomeBytes.Length; Stream newStream = req.GetRequestStream(); newStream.Write(SomeBytes, 0, SomeBytes.Length); newStream.Close(); } else { req.ContentLength = 0; } res = (HttpWebResponse)req.GetResponse(); cookieheader = req.CookieContainer.GetCookieHeader(new Uri(url)); HttpContext.Current.Application.Lock(); HttpContext.Current.Application["cookieheader"] = cookieheader; HttpContext.Current.Application.UnLock();Stream ReceiveStream = res.GetResponseStream(); Encoding encode = System.Text.Encoding.GetEncoding("utf-8"); StreamReader sr = new StreamReader( ReceiveStream, encode ); Char[] read = new Char[256]; int count = sr.Read( read, 0, 256 ); while (count > 0) { String str = new String(read, 0, count); strResult += str; count = sr.Read(read, 0, 256); } } catch(Exception e) { strResult = e.ToString(); } finally { if ( res != null ) { res.Close(); } }return strResult; } public static string getPage(String url, String paramList) { HttpWebResponse res = null; string strResult = "";try {HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url); req.Method = "POST"; req.KeepAlive = true; req.ContentType = "application/x-www-form-urlencoded"; CookieContainer cookieCon = new CookieContainer(); req.CookieContainer = cookieCon; req.CookieContainer.SetCookies(new Uri(url),cookieheader); StringBuilder UrlEncoded = new StringBuilder(); Char[] reserved = {?, =, &}; byte[] SomeBytes = null;if (paramList != null) { int i=0, j; while(i<paramList.Length) { j=paramList.IndexOfAny(reserved, i); if (j==-1) { UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, paramList.Length-i))); break; } UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, j-i))); UrlEncoded.Append(paramList.Substring(j,1)); i = j+1; } SomeBytes = Encoding.UTF8.GetBytes(UrlEncoded.ToString()); req.ContentLength = SomeBytes.Length; Stream newStream = req.GetRequestStream(); newStream.Write(SomeBytes, 0, SomeBytes.Length); newStream.Close(); } else { req.ContentLength = 0; } res = (HttpWebResponse)req.GetResponse(); Stream ReceiveStream = res.GetResponseStream(); Encoding encode = System.Text.Encoding.GetEncoding("utf-8"); StreamReader sr = new StreamReader( ReceiveStream, encode ); Char[] read = new Char[256]; int count = sr.Read( read, 0, 256 ); while (count > 0) { String str = new String(read, 0, count); strResult += str; count = sr.Read(read, 0, 256); } } catch(Exception e) { strResult = e.ToString(); } finally { if ( res != null ) { res.Close(); } }return strResult; } #region Web Form Designer generated code override protected void OnInit(EventArgs e) { // // CODEGEN: This call is required by the ASP.NET Web Form Designer. // InitializeComponent(); base.OnInit(e); }/// <summary> /// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// </summary> private void InitializeComponent() { this.Load += new System.EventHandler(this.Page_Load);} #endregion} } 網絡的神奇作用吸引著越來越多的用戶加入其中，正因如此，網絡的承受能力也面臨著越來越嚴峻的考驗―從硬件上、軟件上、所用標準上......，各項技術都需要適時應勢，對應發展，這正是網絡迅速走向進步的催化劑。 |
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