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灵活调用xsl来解析xml文档(js异步)

程序员文章站 2022-03-10 12:25:24
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1.新建一个vs2003的web工程,取名为xmlTest

2.将工程目录下的WebForm1.aspx中内容全部删除,只留下顶部的一条语句:

<%@ Page language="c#" Codebehind="WebForm1.aspx.cs" AutoEventWireup="false" Inherits="XMLTest.WebForm1" %>

3.修改WebForm1.aspx.cs中内容,在Page_Load中加入:

以下是引用片段:

    XmlDocument doc=new XmlDocument(); 
    String xmlfile=string.Empty; 
    xmlfile=Context.Request.PhysicalapplicationPath+(Request.QueryString["sel"].ToString()=="xml"?"\\hello.xml":"\\hello.xsl"); 
    doc.Load(xmlfile); 
    Response.Write(doc.InnerXml);

4.在工程根目录下新增test.htm,并设为工程首页:

以下是引用片段:

<html> 
<head> 
  <title></title> 
</head> 
<body> 
  <div id="resTree"></div> 
  <FONT face="宋体"></FONT><input type="button" value="执行" onclick="GetXml()"><BR> 
  <script language="JScript"> 
  var srcTree,xsltTree,xt; 
  var http_request = false; 
    
  function GetXml() 
  {     
   srcTree = new ActiveXObject("Msxml2.FreeThreadedDOMDocument"); 
    srcTree.async=false; 
    xsltTree= new ActiveXObject("Msxml2.FreeThreadedDOMDocument"); 
    xsltTree.async = false; 
    xt=new ActiveXObject("MSXML2.XSLTemplate"); 
   resTree.innerHTML=""; 
    makeRequest("WebForm1.aspx?sel=xml",GetXml_CB); 
  } 
     
    function makeRequest(url,callback) { 
        http_request = false; 
        if (window.xmlhttpRequest) { // Mozilla, Safari,... 
            http_request = new XMLHttPRequest(); 
            if (http_request.overrideMimeType) { 
                http_request.overrideMimeType('text/xml'); 
            } 
        } else if (window.ActiveXObject) { // IE 
            try { 
                http_request = new ActiveXObject("Msxml2.XMLHTTP"); 
            } catch (e) { 
                try { 
                    http_request = new ActiveXObject("Microsoft.XMLHTTP"); 
                } catch (e) {} 
            } 
        }
        if (!http_request) { 
            alert('Giving up :( Cannot create an XMLHTTP instance'); 
            return false; 
        } 
        http_request.onreadystatechange = callback; 
        http_request.open('GET', url, true); 
        http_request.send(null); 
    }
    function GetXml_CB() {
        if (http_request.readyState == 4) { 
            if (http_request.status == 200) {     
    srcTree.loadXML(http_request.responseText); 
    makeRequest("WebForm1.aspx?sel=xsl",GetXsl_CB); 
            } else { 
                alert('There was a problem with the request.'); 
            } 
        }
    } 
     
    function GetXsl_CB(){ 
       if (http_request.readyState == 4) { 
         if (http_request.status == 200) { 
       xsltTree.loadXML(http_request.responseText); 
       xt.stylesheet=xsltTree; 
       var proc=xt.createProcessor(); 
       proc.input=srcTree; 
       proc.transform(); 
       resTree.innerHTML=proc.output; 
            } else { 
                alert('There was a problem with the request.'); 
            } 
        } 
   
    }
    function makeRequest(url,callback) { 
     http_request = false; 
     if (window.XMLHttpRequest) { // Mozilla, Safari,... 
            http_request = new XMLHttpRequest(); 
            if (http_request.overrideMimeType) { 
                http_request.overrideMimeType('text/xml'); 
            } 
        } else if (window.ActiveXObject) { // IE 
            try { 
                http_request = new ActiveXObject("Msxml2.XMLHTTP"); 
            } catch (e) { 
                try { 
                    http_request = new ActiveXObject("Microsoft.XMLHTTP"); 
                } catch (e) {} 
            } 
        }
        if (!http_request) { 
            alert('Giving up :( Cannot create an XMLHTTP instance'); 
            return false; 
        } 
        http_request.onreadystatechange = callback; 
        http_request.open('GET', url, true); 
        http_request.send(null); 
    }
  </script>
</body> 
</html>

5.运行工程,看看效果吧!

hello.xml(注意:我的xml文档中并没有指定对应的xsl解析文件名)

以下是引用片段:

<?xml version='1.0'?>
<breakfast-menu> 
  <food> 
    <name>Belgian Waffles</name> 
    <price>$5.95</price> 
    <description>Two of our famous Belgian Waffles  
      with plenty of real maple syrup.</description> 
    <calories>650</calories> 
  </food> 
  <food> 
    <name>Strawberry Belgian Waffles</name> 
    <price>$7.95</price> 
    <description>Light Belgian waffles covered with  
     strawberries and whipped cream.</description> 
    <calories>900</calories> 
  </food> 
  <food> 
    <name>Berry-Berry Belgian Waffles</name> 
    <price>$8.95</price> 
    <description>Light Belgian waffles covered  
      with an assortment of fresh berries  
      and whipped cream.</description> 
    <calories>900</calories> 
  </food> 
  <food> 
    <name>French Toast</name> 
    <price>$4.50</price> 
    <description>Thick slices made from our homemade  
     sourdough bread.</description> 
    <calories>600</calories> 
  </food> 
  <food> 
    <name>Homestyle Breakfast</name> 
    <price>$6.95</price> 
    <description>Two eggs, bacon or sausage, toast,  
      and our ever-popular hash browns.</description> 
    <calories>950</calories> 
  </food> 
</breakfast-menu>

hello.xsl

以下是引用片段:

<?xml version="1.0"?> 
<xsl:stylesheet version="1.0"  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> 
  <xsl:template match="/breakfast-menu">
        <xsl:for-each select="food"> 
          <DIV STYLE="background-color:teal; color:white; padding:4px"> 
            <SPAN STYLE="font-weight:bold; color:white"><xsl:value-of select="name"/></SPAN> 
            至 <xsl:value-of select="price"/> 
          </DIV> 
          <DIV STYLE="margin-left:20px; margin-bottom:1em; font-size:10pt"> 
            <xsl:value-of select="description"/> 
            <SPAN STYLE="font-style:italic"> 
              <xsl:value-of select="calories"/> 嘿嘿 
            </SPAN> 
          </DIV> 
        </xsl:for-each>
  </xsl:template> 
</xsl:stylesheet>

xml文档只有纯粹的数据,如果需要显示到html页面中的话,一般需要使用定制的xsl文档来解析,或者手工通过js来读取xml中的值显示到html中的dom树中,当使用xsl文档来解析时,相应的xml文档中必须指定对应的xsl文档才能正常显示,但当有些程序动态输出xml文档时,并没有指定相应的xsl文档,这时就必须通过其它途径来加载相应的xsl文档来解析,当然,在服务器端输出xml文档时,通过一些xml api也可以实现,我这儿描述的是通过js来实现的一种方式。用这种方式的话,就抛开了服务器平台的限制,服务器端只需要输出相应的xml文档(.net/j2ee都可以),并且将对应的xsl文档输出给客户端(可以输出流或直接在客户端加载xsl文档)。

这里有几个需要注意的地方,我们一般是使用Msxml2.Document组件来加载xml文档的,但当动态使用xsl解析xml文档时,必须使用Msxml2.FreeThreadedDOMDocument这种*线程的组件,同时使用MSXML2.XSLTemplate模板组件来加载xml,xsl数据,通过MSXML2.XSLTemplate的transform方法,就可以动态的用xsl来解析xml数据了,另外,IE5开始,系统默认的xml组件是msxml2,如果需要使用更新的msxml组件需要安装更新的msxml组件包,并指定新的名称,例如Msxml2.FreeThreadedDOMDocument.4.0,现在最新的msxml组件是6.0beta,可在M$网站下载。

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