private async void btnStart_Click(object sender, EventArgs e)
{
//更新界面按钮的属性值
btnStart.Enabled = false;
btnStop.Enabled = !btnStart.Enabled;
#region 从文本框中提取url信息
string webSite = txtWebSite.Text;
if (string.IsNullOrWhiteSpace(webSite))
{
MessageBox.Show("域名为空！");
btnStart.Enabled = true;
btnStop.Enabled = !btnStart.Enabled;
return;
}
if (!webSite.Contains("http"))
{
webSite = "http://" + webSite;
}
while (webSite[webSite.Length - 1] == '/')
{
webSite = webSite.Substring(0, webSite.Length - 1);
}
//检查地址是否发生变化
if (websiteCopy != webSite)
{
dataGridViewTitleURL.Rows.Clear();
urls.Clear();
urlsToBrowse.Clear();
}
#endregion
Crawler crawler = new Crawler();
try
{
#region 根据网站域名提取种子url
if (urls.Count == 0 && urlsToBrowse.Count == 0)
{
List<string> hostBasedHttpURL = await crawler.GetTitleAndHostBasedHTTPURLsFromURL(webSite);
//第一个是Title信息，需要移除掉
if (hostBasedHttpURL.Count > 0)
{
//先提取信息到界面上
dataGridViewTitleURL.Rows.Add(hostBasedHttpURL[0], webSite);
dataGridViewTitleURL.Rows[dataGridViewTitleURL.Rows.Count - 2].HeaderCell.Value = (dataGridViewTitleURL.Rows.Count - 1).ToString();
hostBasedHttpURL.RemoveAt(0);
}
urls.Add(webSite);
foreach (string url in hostBasedHttpURL)
{
if(urls.Add(url))
{
urlsToBrowse.Enqueue(url);
}
}
}
#endregion
#region 根据已有url和初始索引位置，不断地爬取Title和url信息
Method method = this.ThreadMethod;
//开启4个线程：3个互斥锁，至少将代码划分为4个执行区域
for (int temp = 0; temp < 4; temp++)
{
this.Invoke(method);
}
#endregion
}
catch (Exception except)
{
MessageBox.Show(except.Message);
}
finally
{
crawler.Dispose();
}
//最后显示爬出的url数量和Title数量
//MessageBox.Show("url有" + urls.Count + "\n" + "title有" + (dataGridViewTitleURL.Rows.Count - 1));
//备份一份域名
websiteCopy = webSite;
//更新界面按钮的属性值
//btnStart.Enabled = true;
//btnStop.Enabled = !btnStart.Enabled;
lblUrls.Text = "URL：" + urls.Count;
lblTitles.Text = "TITLE：" + (dataGridViewTitleURL.Rows.Count - 1);
}
/// <summary>
/// 异步函数：线程方法
/// </summary>
/// <param name="crawler"></param>
private async void ThreadMethod()
{
Crawler crawler = new Crawler();
while (urlsToBrowse.Count != 0 && btnStart.Enabled == false)
{
string url, title;
//队列互斥锁
lock (queueLock)
{
//i++;
//url = urls.ElementAt(i);
url = urlsToBrowse.Dequeue();
title = "";
}
//获取同一域名下的http超链接以及Title信息
List<string> hostBasedHttpURL = await crawler.GetTitleAndHostBasedHTTPURLsFromURL(url);
//先提取Title信息
if (hostBasedHttpURL.Count > 0)
{
title = hostBasedHttpURL[0];
hostBasedHttpURL.RemoveAt(0);
}
#region 添加Title和url到datagridview
try
{
//UI互斥锁
lock (UILock)
{
dataGridViewTitleURL.Rows.Add(title, url);
dataGridViewTitleURL.Rows[dataGridViewTitleURL.Rows.Count - 2].HeaderCell.Value = (dataGridViewTitleURL.Rows.Count - 1).ToString();
if (btnStopRoll.Text == "停止滚动")
{
dataGridViewTitleURL.FirstDisplayedScrollingRowIndex = dataGridViewTitleURL.Rows.Count - 1;
}
this.lblUrls.Text = "URL: " + urls.Count.ToString();
this.lblTitles.Text = "TITLE: " + (dataGridViewTitleURL.Rows.Count - 1).ToString();
}
}
catch (Exception)
{
//do nothing。
}
#endregion
foreach (string each in hostBasedHttpURL)
{
//写互斥锁
lock (URLLock)
{
if (urls.Add(each))
{
lock (queueLock)
{
urlsToBrowse.Enqueue(each);
}
}
}
}
}
crawler.Dispose();
}