How to Scrape Data from Websites in C

所需技能

1. 掌握编程基础，并具备使用 C# 或 VB.NET 等 Microsoft 编程语言的技能
2. 具备Web技术（HTML、JavaScript、jQuery、CSS等）及其工作原理的基础知识
3. 具备 DOM、XPath、HTML 和 CSS 选择器的基础知识

工具

1. Microsoft Visual Studio 2010 或更高版本
2. 浏览器扩展程序，例如 Chrome 的 Web Inspector 或 Firefox 的 Firebug

使用 NuGet 安装

手动安装

1. 前往 </https:>
2. 点击 IronWebScraper 或直接通过 URL 访问其页面 https://ironsoftware.com/csharp/webscraper/
3. 点击"下载 DLL"。
4. 解压下载的压缩文件

5. 在 Visual Studio 中右键单击项目 -> 添加 -> 引用 -> 浏览

   

6. 转到解压后的文件夹 -> netstandard2.0 -> 并全选 .dll 文件

   

7. 完成！

创建 IronWebscraper 示例的步骤

1. 创建一个文件夹并将其命名为"HelloScraperSample"

2. 然后添加一个新类，并将其命名为 HelloScraper

3. 将此代码片段添加到 HelloScraper

   public class HelloScraper : WebScraper
   {
       /// <summary>
       /// Override this method to initialize your web scraper.
       /// Important tasks will be to request at least one start URL and set allowed/banned domain or URL patterns.
       /// </summary>
       public override void Init()
       {
           License.LicenseKey = "LicenseKey"; // Write License Key
           this.LoggingLevel = WebScraper.LogLevel.All; // Log all events
           this.Request("https://blog.scrapinghub.com", Parse); // Initialize a web request to the given URL
       }
   
       /// <summary>
       /// Override this method to create the default Response handler for your web scraper.
       /// If you have multiple page types, you can add additional similar methods.
       /// </summary>
       /// <param name="response">The HTTP Response object to parse</param>
       public override void Parse(Response response)
       {
           // Set working directory for the project
           this.WorkingDirectory = AppSetting.GetAppRoot() + @"\HelloScraperSample\Output\";
           // Loop on all links
           foreach (var titleLink in response.Css("h2.entry-title a"))
           {
               // Read link text
               string title = titleLink.TextContentClean;
               // Save result to file
               Scrape(new ScrapedData() { { "Title", title } }, "HelloScraper.json");
           }
   
           // Loop on all links for pagination
           if (response.CssExists("div.prev-post > a[href]"))
           {
               // Get next page URL
               var nextPage = response.Css("div.prev-post > a[href]")[0].Attributes["href"];
               // Scrape next URL
               this.Request(nextPage, Parse);
           }
       }
   }

   public class HelloScraper : WebScraper
   {
       /// <summary>
       /// Override this method to initialize your web scraper.
       /// Important tasks will be to request at least one start URL and set allowed/banned domain or URL patterns.
       /// </summary>
       public override void Init()
       {
           License.LicenseKey = "LicenseKey"; // Write License Key
           this.LoggingLevel = WebScraper.LogLevel.All; // Log all events
           this.Request("https://blog.scrapinghub.com", Parse); // Initialize a web request to the given URL
       }
   
       /// <summary>
       /// Override this method to create the default Response handler for your web scraper.
       /// If you have multiple page types, you can add additional similar methods.
       /// </summary>
       /// <param name="response">The HTTP Response object to parse</param>
       public override void Parse(Response response)
       {
           // Set working directory for the project
           this.WorkingDirectory = AppSetting.GetAppRoot() + @"\HelloScraperSample\Output\";
           // Loop on all links
           foreach (var titleLink in response.Css("h2.entry-title a"))
           {
               // Read link text
               string title = titleLink.TextContentClean;
               // Save result to file
               Scrape(new ScrapedData() { { "Title", title } }, "HelloScraper.json");
           }
   
           // Loop on all links for pagination
           if (response.CssExists("div.prev-post > a[href]"))
           {
               // Get next page URL
               var nextPage = response.Css("div.prev-post > a[href]")[0].Attributes["href"];
               // Scrape next URL
               this.Request(nextPage, Parse);
           }
       }
   }

   Public Class HelloScraper
   	Inherits WebScraper
   
   	''' <summary>
   	''' Override this method to initialize your web scraper.
   	''' Important tasks will be to request at least one start URL and set allowed/banned domain or URL patterns.
   	''' </summary>
   	Public Overrides Sub Init()
   		License.LicenseKey = "LicenseKey" ' Write License Key
   		Me.LoggingLevel = WebScraper.LogLevel.All ' Log all events
   		Me.Request("https://blog.scrapinghub.com", AddressOf Parse) ' Initialize a web request to the given URL
   	End Sub
   
   	''' <summary>
   	''' Override this method to create the default Response handler for your web scraper.
   	''' If you have multiple page types, you can add additional similar methods.
   	''' </summary>
   	''' <param name="response">The HTTP Response object to parse</param>
   	Public Overrides Sub Parse(ByVal response As Response)
   		' Set working directory for the project
   		Me.WorkingDirectory = AppSetting.GetAppRoot() & "\HelloScraperSample\Output\"
   		' Loop on all links
   		For Each titleLink In response.Css("h2.entry-title a")
   			' Read link text
   			Dim title As String = titleLink.TextContentClean
   			' Save result to file
   			Scrape(New ScrapedData() From {
   				{ "Title", title }
   			},
   			"HelloScraper.json")
   		Next titleLink
   
   		' Loop on all links for pagination
   		If response.CssExists("div.prev-post > a[href]") Then
   			' Get next page URL
   			Dim nextPage = response.Css("div.prev-post > a[href]")(0).Attributes("href")
   			' Scrape next URL
   			Me.Request(nextPage, AddressOf Parse)
   		End If
   	End Sub
   End Class

   $vbLabelText   $csharpLabel

4. 现在要开始抓取，请将以下代码片段添加到 Main

   static void Main(string[] args)
   {
       // Create Object From Hello Scrape class
       HelloScraperSample.HelloScraper scrape = new HelloScraperSample.HelloScraper();
       // Start Scraping
       scrape.Start();
   }

   static void Main(string[] args)
   {
       // Create Object From Hello Scrape class
       HelloScraperSample.HelloScraper scrape = new HelloScraperSample.HelloScraper();
       // Start Scraping
       scrape.Start();
   }

   Shared Sub Main(ByVal args() As String)
   	' Create Object From Hello Scrape class
   	Dim scrape As New HelloScraperSample.HelloScraper()
   	' Start Scraping
   	scrape.Start()
   End Sub

   $vbLabelText   $csharpLabel
5. 翻译结果将保存为格式为 WebScraper.WorkingDirectory/classname.Json 的文件

代码概述

Scrape.Start() 将按以下方式触发抓取逻辑：

1. 调用 Init() 方法来初始化变量、抓取属性及行为属性。
2. 使用 Request("https://blog.scrapinghub.com", Parse) 在 Init() 中设置起始页面请求。
3. 支持并行处理多个 HTTP 请求和线程，使代码保持同步，更易于调试。
4. Parse() 方法在 Init() 之后被触发，用于处理响应，通过 CSS 选择器提取数据并将其保存为 JSON 格式。

抓取在线电影网站

让我们通过一个从电影网站抓取数据的示例来说明。

添加一个新类并将其命名为 MovieScraper：

HTML 结构

以下是网站首页HTML代码的片段：

<div id="movie-featured" class="movies-list movies-list-full tab-pane in fade active">
    <div data-movie-id="20746" class="ml-item">
        <a href="https://website.com/film/king-arthur-legend-of-the-sword-20746/">
            <span class="mli-quality">CAM</span>
            <img data-original="https://img.gocdn.online/2017/05/16/poster/2116d6719c710eabe83b377463230fbe-king-arthur-legend-of-the-sword.jpg" 
                 class="lazy thumb mli-thumb" alt="King Arthur: Legend of the Sword"
                  src="https://img.gocdn.online/2017/05/16/poster/2116d6719c710eabe83b377463230fbe-king-arthur-legend-of-the-sword.jpg" 
                 style="display: inline-block;">
            <span class="mli-info"><h2>King Arthur: Legend of the Sword</h2></span>
        </a>
    </div>
    <div data-movie-id="20724" class="ml-item">
        <a href="https://website.com/film/snatched-20724/" >
            <span class="mli-quality">CAM</span>
            <img data-original="https://img.gocdn.online/2017/05/16/poster/5ef66403dc331009bdb5aa37cfe819ba-snatched.jpg" 
                 class="lazy thumb mli-thumb" alt="Snatched" 
                 src="https://img.gocdn.online/2017/05/16/poster/5ef66403dc331009bdb5aa37cfe819ba-snatched.jpg" 
                 style="display: inline-block;">
            <span class="mli-info"><h2>Snatched</h2></span>
        </a>
    </div>
</div>

<div id="movie-featured" class="movies-list movies-list-full tab-pane in fade active">
    <div data-movie-id="20746" class="ml-item">
        <a href="https://website.com/film/king-arthur-legend-of-the-sword-20746/">
            <span class="mli-quality">CAM</span>
            <img data-original="https://img.gocdn.online/2017/05/16/poster/2116d6719c710eabe83b377463230fbe-king-arthur-legend-of-the-sword.jpg" 
                 class="lazy thumb mli-thumb" alt="King Arthur: Legend of the Sword"
                  src="https://img.gocdn.online/2017/05/16/poster/2116d6719c710eabe83b377463230fbe-king-arthur-legend-of-the-sword.jpg" 
                 style="display: inline-block;">
            <span class="mli-info"><h2>King Arthur: Legend of the Sword</h2></span>
        </a>
    </div>
    <div data-movie-id="20724" class="ml-item">
        <a href="https://website.com/film/snatched-20724/" >
            <span class="mli-quality">CAM</span>
            <img data-original="https://img.gocdn.online/2017/05/16/poster/5ef66403dc331009bdb5aa37cfe819ba-snatched.jpg" 
                 class="lazy thumb mli-thumb" alt="Snatched" 
                 src="https://img.gocdn.online/2017/05/16/poster/5ef66403dc331009bdb5aa37cfe819ba-snatched.jpg" 
                 style="display: inline-block;">
            <span class="mli-info"><h2>Snatched</h2></span>
        </a>
    </div>
</div>

如我们所见，这里包含电影 ID、标题以及详细页面的链接。 让我们开始抓取这些数据：

public class MovieScraper : WebScraper
{
    public override void Init()
    {
        License.LicenseKey = "LicenseKey";
        this.LoggingLevel = WebScraper.LogLevel.All;
        this.WorkingDirectory = AppSetting.GetAppRoot() + @"\MovieSample\Output\";
        this.Request("www.website.com", Parse);
    }

    public override void Parse(Response response)
    {
        foreach (var div in response.Css("#movie-featured > div"))
        {
            if (div.GetAttribute("class") != "clearfix")
            {
                var movieId = div.GetAttribute("data-movie-id");
                var link = div.Css("a")[0];
                var movieTitle = link.TextContentClean;
                Scrape(new ScrapedData() { { "MovieId", movieId }, { "MovieTitle", movieTitle } }, "Movie.Jsonl");
            }
        }           
    }
}

public class MovieScraper : WebScraper
{
    public override void Init()
    {
        License.LicenseKey = "LicenseKey";
        this.LoggingLevel = WebScraper.LogLevel.All;
        this.WorkingDirectory = AppSetting.GetAppRoot() + @"\MovieSample\Output\";
        this.Request("www.website.com", Parse);
    }

    public override void Parse(Response response)
    {
        foreach (var div in response.Css("#movie-featured > div"))
        {
            if (div.GetAttribute("class") != "clearfix")
            {
                var movieId = div.GetAttribute("data-movie-id");
                var link = div.Css("a")[0];
                var movieTitle = link.TextContentClean;
                Scrape(new ScrapedData() { { "MovieId", movieId }, { "MovieTitle", movieTitle } }, "Movie.Jsonl");
            }
        }           
    }
}

Public Class MovieScraper
	Inherits WebScraper

	Public Overrides Sub Init()
		License.LicenseKey = "LicenseKey"
		Me.LoggingLevel = WebScraper.LogLevel.All
		Me.WorkingDirectory = AppSetting.GetAppRoot() & "\MovieSample\Output\"
		Me.Request("www.website.com", AddressOf Parse)
	End Sub

	Public Overrides Sub Parse(ByVal response As Response)
		For Each div In response.Css("#movie-featured > div")
			If div.GetAttribute("class") <> "clearfix" Then
				Dim movieId = div.GetAttribute("data-movie-id")
				Dim link = div.Css("a")(0)
				Dim movieTitle = link.TextContentClean
				Scrape(New ScrapedData() From {
					{ "MovieId", movieId },
					{ "MovieTitle", movieTitle }
				},
				"Movie.Jsonl")
			End If
		Next div
	End Sub
End Class

结构化电影类

为了存储格式化数据，让我们实现一个电影类：

public class Movie
{
    public int Id { get; set; }
    public string Title { get; set; }
    public string URL { get; set; }
}

public class Movie
{
    public int Id { get; set; }
    public string Title { get; set; }
    public string URL { get; set; }
}

Public Class Movie
    Public Property Id As Integer
    Public Property Title As String
    Public Property URL As String
End Class

现在更新我们的代码，使用 Movie 类：

public class MovieScraper : WebScraper
{
    public override void Init()
    {
        License.LicenseKey = "LicenseKey";
        this.LoggingLevel = WebScraper.LogLevel.All;
        this.WorkingDirectory = AppSetting.GetAppRoot() + @"\MovieSample\Output\";
        this.Request("https://website.com/", Parse);
    }

    public override void Parse(Response response)
    {
        foreach (var div in response.Css("#movie-featured > div"))
        {
            if (div.GetAttribute("class") != "clearfix")
            {
                var movie = new Movie
                {
                    Id = Convert.ToInt32(div.GetAttribute("data-movie-id")),
                    Title = div.Css("a")[0].TextContentClean,
                    URL = div.Css("a")[0].Attributes["href"]
                };
                Scrape(movie, "Movie.Jsonl");
            }
        }
    }
}

public class MovieScraper : WebScraper
{
    public override void Init()
    {
        License.LicenseKey = "LicenseKey";
        this.LoggingLevel = WebScraper.LogLevel.All;
        this.WorkingDirectory = AppSetting.GetAppRoot() + @"\MovieSample\Output\";
        this.Request("https://website.com/", Parse);
    }

    public override void Parse(Response response)
    {
        foreach (var div in response.Css("#movie-featured > div"))
        {
            if (div.GetAttribute("class") != "clearfix")
            {
                var movie = new Movie
                {
                    Id = Convert.ToInt32(div.GetAttribute("data-movie-id")),
                    Title = div.Css("a")[0].TextContentClean,
                    URL = div.Css("a")[0].Attributes["href"]
                };
                Scrape(movie, "Movie.Jsonl");
            }
        }
    }
}

Public Class MovieScraper
	Inherits WebScraper

	Public Overrides Sub Init()
		License.LicenseKey = "LicenseKey"
		Me.LoggingLevel = WebScraper.LogLevel.All
		Me.WorkingDirectory = AppSetting.GetAppRoot() & "\MovieSample\Output\"
		Me.Request("https://website.com/", AddressOf Parse)
	End Sub

	Public Overrides Sub Parse(ByVal response As Response)
		For Each div In response.Css("#movie-featured > div")
			If div.GetAttribute("class") <> "clearfix" Then
				Dim movie As New Movie With {
					.Id = Convert.ToInt32(div.GetAttribute("data-movie-id")),
					.Title = div.Css("a")(0).TextContentClean,
					.URL = div.Css("a")(0).Attributes("href")
				}
				Scrape(movie, "Movie.Jsonl")
			End If
		Next div
	End Sub
End Class

详细页面抓取

让我们扩展 Movie 类，为其添加用于存储详细信息的新属性：

public class Movie
{
    public int Id { get; set; }
    public string Title { get; set; }
    public string URL { get; set; }
    public string Description { get; set; }
    public List<string> Genre { get; set; }
    public List<string> Actor { get; set; }
}

public class Movie
{
    public int Id { get; set; }
    public string Title { get; set; }
    public string URL { get; set; }
    public string Description { get; set; }
    public List<string> Genre { get; set; }
    public List<string> Actor { get; set; }
}

Public Class Movie
    Public Property Id As Integer
    Public Property Title As String
    Public Property URL As String
    Public Property Description As String
    Public Property Genre As List(Of String)
    Public Property Actor As List(Of String)
End Class

然后导航至"详细信息"页面进行抓取，利用 IronWebScraper 的扩展功能：

public class MovieScraper : WebScraper
{
    public override void Init()
    {
        License.LicenseKey = "LicenseKey";
        this.LoggingLevel = WebScraper.LogLevel.All;
        this.WorkingDirectory = AppSetting.GetAppRoot() + @"\MovieSample\Output\";
        this.Request("https://domain/", Parse);
    }

    public override void Parse(Response response)
    {
        foreach (var div in response.Css("#movie-featured > div"))
        {
            if (div.GetAttribute("class") != "clearfix")
            {
                var movie = new Movie
                {
                    Id = Convert.ToInt32(div.GetAttribute("data-movie-id")),
                    Title = div.Css("a")[0].TextContentClean,
                    URL = div.Css("a")[0].Attributes["href"]
                };
                this.Request(movie.URL, ParseDetails, new MetaData() { { "movie", movie } });
            }
        }           
    }

    public void ParseDetails(Response response)
    {
        var movie = response.MetaData.Get<Movie>("movie");
        var div = response.Css("div.mvic-desc")[0];
        movie.Description = div.Css("div.desc")[0].TextContentClean;
        movie.Genre = div.Css("div > p > a").Select(element => element.TextContentClean).ToList();
        movie.Actor = div.Css("div > p:nth-child(2) > a").Select(element => element.TextContentClean).ToList();

        Scrape(movie, "Movie.Jsonl");
    }
}

public class MovieScraper : WebScraper
{
    public override void Init()
    {
        License.LicenseKey = "LicenseKey";
        this.LoggingLevel = WebScraper.LogLevel.All;
        this.WorkingDirectory = AppSetting.GetAppRoot() + @"\MovieSample\Output\";
        this.Request("https://domain/", Parse);
    }

    public override void Parse(Response response)
    {
        foreach (var div in response.Css("#movie-featured > div"))
        {
            if (div.GetAttribute("class") != "clearfix")
            {
                var movie = new Movie
                {
                    Id = Convert.ToInt32(div.GetAttribute("data-movie-id")),
                    Title = div.Css("a")[0].TextContentClean,
                    URL = div.Css("a")[0].Attributes["href"]
                };
                this.Request(movie.URL, ParseDetails, new MetaData() { { "movie", movie } });
            }
        }           
    }

    public void ParseDetails(Response response)
    {
        var movie = response.MetaData.Get<Movie>("movie");
        var div = response.Css("div.mvic-desc")[0];
        movie.Description = div.Css("div.desc")[0].TextContentClean;
        movie.Genre = div.Css("div > p > a").Select(element => element.TextContentClean).ToList();
        movie.Actor = div.Css("div > p:nth-child(2) > a").Select(element => element.TextContentClean).ToList();

        Scrape(movie, "Movie.Jsonl");
    }
}

Public Class MovieScraper
	Inherits WebScraper

	Public Overrides Sub Init()
		License.LicenseKey = "LicenseKey"
		Me.LoggingLevel = WebScraper.LogLevel.All
		Me.WorkingDirectory = AppSetting.GetAppRoot() & "\MovieSample\Output\"
		Me.Request("https://domain/", AddressOf Parse)
	End Sub

	Public Overrides Sub Parse(ByVal response As Response)
		For Each div In response.Css("#movie-featured > div")
			If div.GetAttribute("class") <> "clearfix" Then
				Dim movie As New Movie With {
					.Id = Convert.ToInt32(div.GetAttribute("data-movie-id")),
					.Title = div.Css("a")(0).TextContentClean,
					.URL = div.Css("a")(0).Attributes("href")
				}
				Me.Request(movie.URL, AddressOf ParseDetails, New MetaData() From {
					{ "movie", movie }
				})
			End If
		Next div
	End Sub

	Public Sub ParseDetails(ByVal response As Response)
		Dim movie = response.MetaData.Get(Of Movie)("movie")
		Dim div = response.Css("div.mvic-desc")(0)
		movie.Description = div.Css("div.desc")(0).TextContentClean
		movie.Genre = div.Css("div > p > a").Select(Function(element) element.TextContentClean).ToList()
		movie.Actor = div.Css("div > p:nth-child(2) > a").Select(Function(element) element.TextContentClean).ToList()

		Scrape(movie, "Movie.Jsonl")
	End Sub
End Class

HttpIdentity 功能

某些系统要求用户登录后才能查看内容； 请使用 HttpIdentity 表示凭据：

HttpIdentity id = new HttpIdentity
{
    NetworkUsername = "username",
    NetworkPassword = "pwd"
};
Identities.Add(id);

HttpIdentity id = new HttpIdentity
{
    NetworkUsername = "username",
    NetworkPassword = "pwd"
};
Identities.Add(id);

Dim id As New HttpIdentity With {
	.NetworkUsername = "username",
	.NetworkPassword = "pwd"
}
Identities.Add(id)

启用 Web 缓存

缓存请求的页面以便在开发过程中重复使用：

public override void Init()
{
    License.LicenseKey = "LicenseKey";
    this.LoggingLevel = WebScraper.LogLevel.All;
    this.WorkingDirectory = AppSetting.GetAppRoot() + @"\ShoppingSiteSample\Output\";
    EnableWebCache();
    this.Request("http://www.WebSite.com", Parse);
}

public override void Init()
{
    License.LicenseKey = "LicenseKey";
    this.LoggingLevel = WebScraper.LogLevel.All;
    this.WorkingDirectory = AppSetting.GetAppRoot() + @"\ShoppingSiteSample\Output\";
    EnableWebCache();
    this.Request("http://www.WebSite.com", Parse);
}

Public Overrides Sub Init()
	License.LicenseKey = "LicenseKey"
	Me.LoggingLevel = WebScraper.LogLevel.All
	Me.WorkingDirectory = AppSetting.GetAppRoot() & "\ShoppingSiteSample\Output\"
	EnableWebCache()
	Me.Request("http://www.WebSite.com", Parse)
End Sub

限流

public override void Init()
{
    License.LicenseKey = "LicenseKey";
    this.LoggingLevel = WebScraper.LogLevel.All;
    this.WorkingDirectory = AppSetting.GetAppRoot() + @"\ShoppingSiteSample\Output\";
    this.MaxHttpConnectionLimit = 80;
    this.RateLimitPerHost = TimeSpan.FromMilliseconds(50);
    this.OpenConnectionLimitPerHost = 25;
    this.ObeyRobotsDotTxt = false;
    this.ThrottleMode = Throttle.ByDomainHostName;
    this.Request("https://www.Website.com", Parse);
}

public override void Init()
{
    License.LicenseKey = "LicenseKey";
    this.LoggingLevel = WebScraper.LogLevel.All;
    this.WorkingDirectory = AppSetting.GetAppRoot() + @"\ShoppingSiteSample\Output\";
    this.MaxHttpConnectionLimit = 80;
    this.RateLimitPerHost = TimeSpan.FromMilliseconds(50);
    this.OpenConnectionLimitPerHost = 25;
    this.ObeyRobotsDotTxt = false;
    this.ThrottleMode = Throttle.ByDomainHostName;
    this.Request("https://www.Website.com", Parse);
}

Public Overrides Sub Init()
	License.LicenseKey = "LicenseKey"
	Me.LoggingLevel = WebScraper.LogLevel.All
	Me.WorkingDirectory = AppSetting.GetAppRoot() & "\ShoppingSiteSample\Output\"
	Me.MaxHttpConnectionLimit = 80
	Me.RateLimitPerHost = TimeSpan.FromMilliseconds(50)
	Me.OpenConnectionLimitPerHost = 25
	Me.ObeyRobotsDotTxt = False
	Me.ThrottleMode = Throttle.ByDomainHostName
	Me.Request("https://www.Website.com", Parse)
End Sub

如何创建 Windows 窗体应用程序？

请使用 Visual Studio 2013 或更高版本。

1. 打开 Visual Studio。

2. 文件 -> 新建 -> 项目

3. 选择 Visual C# 或 VB -> Windows -> Windows 窗体应用程序。

项目名称：IronScraperSample
位置：在您的磁盘上选择一个位置。

如何创建 ASP.NET Web 窗体应用程序？

1. 打开 Visual Studio。

2. 文件 -> 新建 -> 项目

3. 选择 Visual C# 或 VB -> Web -> ASP.NET Web 应用程序 (.NET Framework)。

项目名称：IronScraperSample
位置：在您的磁盘上选择一个位置。

1. 在您的 ASP.NET 模板中，选择一个空模板并勾选"Web Forms"。

2. 您的基本 ASP.NET Web Form 项目已创建。

点击此处下载完整的教程示例项目代码。