HTMLParser 学习

使用HtmlParser解析HTML 
如果要对HTML进行解析,提取HTML的数据或者修改HTML数据,HtmlParser是一个不错的选择.
使用HtmlParser可以解析本地和网络上的HTML数据:
Parser parser = new Parser( new Winista.Text.HtmlParser.Http.HttpProtocol(new Uri("uriString")));

Parser parser = new Parser( new Winista.Text.HtmlParser.Lex.Lexer( "HtmlString" ) );

System.IO.Stream stream = new System.IO.FileStream( "filePath" , System.IO.FileMode.Open );
Parser parser = new Parser( new Winista.Text.HtmlParser.Lex.Lexer( new Winista.Text.HtmlParser.Lex.Page( stream ,"charSet") ) );还可以分析某些特定节点的数据,使用 NodeClassFilter 指定要分析的节点类型:
NodeFilter filter = new NodeClassFilter( typeof( Winista.Text.HtmlParser.Tags.Div ) );使用Parser实例的Parse方法可以获得节点数组
NodeList nodeList = parser.Parse( null );

NodeList nodeList = parser.Parse( filter);现在分析一下的一段HTML:
<div class="divCss" id="div_1">
    <div name="div" class="divCss" id="div_2">div_2</div>
    <table name="table" id="table_1">
        <tr>
            <td>HtmlParser</td>
            <td><div id="div_3"><font color="red">HtmlParser</font></div></td>
        </tr>
    </table>
</div>
txtResult是显示分析处理后的数据,txtSource是读取HTML数据的文本框
//记录个节点的起始位置,避免重复处理
    IList<int> start = new List<int>( );
    protected void Button1_Click ( object sender , EventArgs e )
    {
        this.txtResult.Text = string.Empty;
        Lexer lexer = new Lexer( this.txtSource.Text );
        Parser parser = new Parser( lexer );
        NodeFilter filter = new NodeClassFilter( typeof( Winista.Text.HtmlParser.Tags.Div ) );
        NodeList nodeList = parser.Parse( null );
        if ( nodeList.Count == 0 )
            txtResult.Text = "没有符合要求的节点";
        else
        {
            for ( int i = 0 ; i < nodeList.Count ; i++ )
            {
                paserData( nodeList[i] );
            }
        }
    }
    private ITag getTag ( INode node )
    {
        if ( node == null )
            return null;
       return node is ITag ? node as ITag : null;
    }

    private void paserData ( INode node)
    {
        ITag tag = getTag( node );
        if ( tag != null && !tag.IsEndTag( ) && !start.Contains(tag.StartPosition))
        {
            object oId = tag.GetAttribute( "ID" );
            object oName = tag.GetAttribute( "name" );
            object oClass = tag.GetAttribute( "class" );
            this.txtResult.Text += tag.TagName + ":\r\nID:" + oId + " Name:" + oName
                   + " Class:" + oClass + " StartPosition:" + tag.StartPosition.ToString( ) + "\r\n";
            start.Add( tag.StartPosition );
        }
        //子节点
        if ( node.Children != null && node.Children.Count > 0 )
        {
            paserData( node.FirstChild );
        }
        //兄弟节点
        INode siblingNode = node.NextSibling;
        while ( siblingNode != null )
        {
            paserData( siblingNode );
            siblingNode = siblingNode.NextSibling;
        }
    }txtResult显示的数据为：
DIV:
ID:div_1 Name: Class:divCss StartPosition:0
DIV:
ID:div_2 Name:div Class:divCss StartPosition:34
TABLE:
ID:table_1 Name:table Class: StartPosition:90
TR:
ID: Name: Class: StartPosition:127
TD:
ID: Name: Class: StartPosition:136
TD:
ID: Name: Class: StartPosition:160
DIV:
ID:div_3 Name: Class: StartPosition:164
FONT:
ID: Name: Class: StartPosition:180
HtmlParser将我们指定的数据给分析出来了,现在来对要分析的数据进行一些修改:给没有name和class属性的指定属性:
           object oId = tag.GetAttribute( "ID" );
            object oName = tag.GetAttribute( "name" );
            object oClass = tag.GetAttribute( "class" );

            if ( oName == null )
            {
                oName = "name";
                tag.SetAttribute( "name" , oName.ToString( ) );
            }
            if ( oClass == null )
            {
                oClass = "class";
                tag.SetAttribute( "name" , oClass.ToString( ) );
            }
            this.txtResult.Text += tag.TagName + ":\r\nID:" + oId + " Name:" + oName
                   + " Class:" + oClass + " StartPosition:" + tag.StartPosition.ToString( ) + "\r\n";
            start.Add( tag.StartPosition );txtResult显示的数据为：
DIV:
ID:div_1 Name:name Class:divCss StartPosition:0
DIV:
ID:div_2 Name:div Class:divCss StartPosition:34
TABLE:
ID:table_1 Name:table Class:class StartPosition:90
TR:
ID: Name:name Class:class StartPosition:127
TD:
ID: Name:name Class:class StartPosition:136
TD:
ID: Name:name Class:class StartPosition:160
DIV:
ID:div_3 Name:name Class:class StartPosition:164
FONT:
ID: Name:name Class:class StartPosition:180
HtmlParser实现了我们的目的,现在在给节点为DIV并且ID为div_3的节点添加一个子节点:
            object oId = tag.GetAttribute( "ID" );
            object oName = tag.GetAttribute( "name" );
            object oClass = tag.GetAttribute( "class" );
            if ( tag.TagName == "DIV" && tag.GetAttribute( "ID" ) == "div_3" )
            {
                INode newNode = new TextNode( "add a new node" );
                tag.Children.Add( newNode );
            }
            this.txtResult.Text += tag.TagName + ":\r\nID:" + oId + " Name:" + oName
                   + " Class:" + oClass + " StartPosition:" + tag.StartPosition.ToString( ) + "\r\n";输出nodeList[0].ToHtml( ):
<div class="divCss" id="div_1">
    <div name="div" class="divCss" id="div_2">div_2</div>
    <table name="table" id="table_1">
        <tr>
            <td>HtmlParser</td>
            <td><div id="div_3"><font color="red">HtmlParser</font>add a new node</div></td>
        </tr>
    </table>
</div>id为div_3的div节点后面加上了要添加的数据.