asp.net(c#)做一个网页数据采集工具

通过这个软件一两天就完成了几千产品数据的录入，可见很多工作不是一味用人工去做，作为一个程序员，就是要让很多让那些经常做重复性的、繁琐的工作中的人解放出来。下面只是写了一些核心代码，而且采集必须要和对应网站相挂钩，作者：郑少群

//提取产品列表页中产品最终页的网页
private void button1_click(object sender, eventargs e)
{
if (textbox1.text.trim() == "" || textbox2.text.trim() == "")
{
messagebox.show("网址和域名不能为空！", "信息提示", messageboxbuttons.ok, messageboxicon.information);
return;
}
try
{
string html = inc.gethtml("http://study.pctoday.net.cn");
//arraylist al = inc.getmatchesstr(html, "<a[^>]*?>.*?</a>");
arraylist al = inc.getmatchesstr(html, @"href\s*=\s*(?:[\'\""\s](?<1>[^\""\']*)[\'\""])");//提取链接


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stringbuilder sb = new stringbuilder();
foreach (object var in al)
{
string a = var.tostring().replace("\"", "").replace("'", "");
a = regex.replace(a, "href=", "", regexoptions.ignorecase | regexoptions.multiline);
if (a.startswith("/"))
a = textbox2.text.trim() + a;
if (!a.startswith("http://"))
a = "http://" + a;
sb.append(a + "\r\n");
}
textbox5.text = sb.tostring();//把提取到网址输出到一个textbox，每个链接占一行



messagebox.show("共提取" + al.count.tostring() + "个链接", "信息提示", messageboxbuttons.ok, messageboxicon.information);

}
catch (exception err)
{
messagebox.show("提取出错！原因：" + err.message, "信息提示", messageboxbuttons.ok, messageboxicon.information);
}

}




//把采集的产品页面html代码进行字符串处理，提取需要的代码，最后保存到本地一个access数据库中，同时提取产品图片地址并自动现在图片到本地images文件夹下

private void backgroundworker1_dowork(object sender, doworkeventargs e)
{
//填充产品表
database.executenonquery("delete from tb_product");
datatable dt2 = new datatable();
oledbconnection conn = new oledbconnection(database.connectionstrings);
oledbdataadapter da = new oledbdataadapter("select * from tb_product", conn);
oledbcommandbuilder cb = new oledbcommandbuilder(da);
da.fill(dt2);
dt2.rows.clear();

backgroundworker worker = (backgroundworker)sender;//这个是做一个进度条

string[] urls = textbox5.text.trim().tolower().replace("\r\n", ",").split(',');
datatable dt = new datatable();
stringbuilder errorstr = new stringbuilder();
string html = "", imagedir = appdomain.currentdomain.basedirectory + "images\\";

//循环每次采集网址
for (int i = 0; i < urls.length; i++)
{
try
{
if (!worker.cancellationpending)
{
if (urls[i] == "")
return;
html = inc.gethtml(urls[i]);//获取该url的html代码
datarow newrow = dt2.newrow();

//产品名
string productname = html.substring(html.indexof("<title>") + 7);
newrow["productname"] = productname.remove(productname.indexof("</title>")).trim();

//产品编号
newrow["modelid"] = newrow["productname"].tostring().substring(newrow["productname"].tostring().indexof("model:") + 6).trim();

//产品介绍，这些都是根据不同网站的html做相应的修改
string introduce = html.substring(html.indexof("product details") + 26);
introduce = introduce.remove(introduce.indexof("</table>") + 8).trim()

newrow["introduce"] = introduce;



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//下载图片
string productimage = html.substring(html.indexof("align=center><img") + 17);
productimage = textbox2.text.trim() + productimage.substring(productimage.indexof("src=\"") + 5);
productimage = productimage.remove(productimage.indexof("\""));
try
{
inc.downfile(productimage, imagedir + productimage.substring(productimage.lastindexof("/") + 1));
}
catch (exception)
{
errorstr.append("下载图片失败，图片地址：" + imagedir + productimage.substring(productimage.lastindexof("/") + 1) + "\r\n");
}


dt2.rows.add(newrow);

//thread.sleep(100);
worker.reportprogress((i + 1) * 100 / urls.length, i);
toolstripstatuslabel1.text = "处理进度:" + (i + 1).tostring() + "/" + urls.length.tostring();//进度条
}

}
catch (exception err)
{
errorstr.append("采集错误：" + err.message + ";网址：" + urls[i] + "\r\n");
}
}
da.update(dt2);
databind(dt2);
showerror(errorstr.tostring());
}

/// <summary>
/// aspx页面生成静态html页面，作者：郑少群
/// </summary>
public static string gethtml(string url)
{
streamreader sr = null;
string str = null;
//读取远程路径
webrequest request = webrequest.create(url);
httpwebresponse response = (httpwebresponse)request.getresponse();
sr = new streamreader(response.getresponsestream(), encoding.getencoding(response.characterset));
str = sr.readtoend();
sr.close();
return str;
}


// 提取html代码中的网址
public static arraylist getmatchesstr(string htmlcode, string strregex)
{
arraylist al = new arraylist();

regex r = new regex(strregex, regexoptions.ignorecase | regexoptions.multiline);
matchcollection m = r.matches(htmlcode);

for (int i = 0; i < m.count; i++)
{
bool rep = false;
string strnew = m[i].tostring();

// 过滤重复的url
foreach (string str in al)
{
if (strnew == str)
{
rep = true;
break;
}
}

if (!rep) al.add(strnew);
}

al.sort();

return al;
}

public static void downfile(string url, string path)
{

httpwebrequest request = (httpwebrequest)webrequest.create(url);
httpwebresponse response = (httpwebresponse)request.getresponse();
stream stream = response.getresponsestream();
long size = response.contentlength;
//创建文件流对象
using (filestream fs = new filestream(path, filemode.openorcreate, fileaccess.write))
{
byte[] b = new byte[1025];
int n = 0;
while ((n = stream.read(b, 0, 1024)) > 0)
{
fs.write(b, 0, n);
}
}
}