C#网页信息采集方法汇总

本文实例总结了三种常用的c#网页信息采集方法。分享给大家供大家参考。具体实现方法如下：

一、通过httpwebresponse 来获取

public static string checkteamsiteurl(string url) 
{ 
        string response = ""; 
        httpwebresponse httpresponse = null; 
 
        //assert: user have access to url  
        try 
        { 
            httpwebrequest httprequest = (httpwebrequest)webrequest.create(url); 
            httprequest.headers.set("pragma", "no-cache"); 
 
                // request.headers.set("keepalive", "true"); 
 
                httprequest.cookiecontainer = new cookiecontainer(); 
 
 
 
                httprequest.referer = url; 
 
                httprequest.useragent = "mozilla/4.0 (compatible; msie 6.0; windows nt 5.0; .net clr 1.1.4322; .net clr 2.0.50727)"; 
 
               
 
            httprequest.credentials = system.net.credentialcache.defaultcredentials; 
            httpresponse = (httpwebresponse)httprequest.getresponse(); 
             
        } 
        catch (exception ex) 
        { 
            throw new applicationexception("http 403 access denied, url: " + url, ex); 
        } 
 
        //if here, the url is correct and the user has access  
        try 
        { 
            string strencod = httpresponse.contenttype; 
            streamreader stream; 
            if (strencod.tolower().indexof("utf") != -1) 
            { 
                stream = new streamreader(httpresponse.getresponsestream(), system.text.encoding.utf8); 
            } 
            else 
            { 
                stream = new streamreader(httpresponse.getresponsestream(), system.text.encoding.default); 
            } 
            
            char[] buff = new char[4000]; 
            stream.readblock(buff,0,4000); 
            response = new string(buff); 
            stream.close(); 
            httpresponse.close(); 
        } 
        catch (exception ex) 
        { 
            throw new applicationexception("http 404 page not found, url: " + url, ex); 
        } 
        return response; 
}

 
二、通过 webresponse 来获取

public static string getpage(string url) 
{
        webresponse result = null; 
        string resultstring = ""; 
        try 
        { 
            webrequest req = webrequest.create(url); 
            req.timeout = 30000; 
            result = req.getresponse(); 
            stream receivestream = result.getresponsestream(); 
 
            //read the stream into a string 
            //streamreader sr = new streamreader(receivestream, system.text.encoding.utf8); 
            string strencod = result.contenttype; 
            streamreader sr; 
            if (strencod.tolower().indexof("utf") != -1) 
            { 
                sr = new streamreader(receivestream, system.text.encoding.utf8); 
            } 
            else 
            { 
                sr = new streamreader(receivestream, system.text.encoding.default); 
            } 
            resultstring = sr.readtoend(); 
            js.alert(resultstring); 
            //console.writeline(resultstring); 
        } 
        catch 
        { 
            throw new exception(); 
        } 
        finally 
        { 
            if (result != null) 
            { 
                result.close(); 
            } 
        } 
        return resultstring; 
}

 
三、通过webclient来获取

public string get(int length) 
{ 
        try 
        { 
            getencodeing(); 
            webclient wb = new webclient(); 
            stream response = wb.openread(url); 
            streamreader reader = new streamreader(response, this.encoding, true, 256000); 
            char[] a = new char[length]; 
            int i  = reader.read(a,0,length); 
            reader.close(); 
            return new string(a); 
        } 
        catch (exception e) 
        { 
            return e.message; 
            //return null; 
        } 
} 
private void getencodeing() 
{
        switch (this.encode) 
        { 
            case "utf-8": encoding = encoding.utf8; break; 
            case "gb2312": encoding = encoding.getencoding("gb2312"); break; 
            case "ascii": encoding = encoding.ascii; break; 
            default: encoding = encoding.getencoding(encode); break; 
        } 
}

希望本文所述对大家的c#程序设计有所帮助。