传智播客：ajax：xpath操作 - habernate的日志 - 网易博客

传智播客：ajax：xpath操作

java 2009-04-09 14:26:29 阅读16 评论0   字号：大中小 订阅

XPath：xml path Language，是用于确定xml某个节点位置的语言。
根据xpath查找节点的JavaScript方法

function selectSingleNode(xmldoc,sXpath){
  if (window.ActiveXObject) {
      //IE浏览器
      return xmldoc.selectSingleNode(sXpath);
  } else if (window.XPathEvaluator) {
      //FireFox类浏览器
      var xpathObj = new XPathEvaluator();
      if (xpathObj) {
          var result = xpathObj.evaluate(sXpath,xmldoc,null,XPathResult.FIRST_ORDERED_NODE_TYPE,null);
          return result.singleNodeValue;
      } else {
          return null;
      }
  } else {
      return null;
  }
}


function selectNodes(xmldoc,sXpath){
  if (window.ActiveXObject) {
      //IE浏览器
      return xmldoc.selectNodes(sXpath);
  } else if (window.XPathEvaluator) {
      //FireFox类浏览器
      var xpathObj = new XPathEvaluator();
      if (xpathObj) {
          var result = xpathObj.evaluate(sXpath,xmldoc,null,XPathResult.ORDERED_NODE_ITERATOR_TYPE,null);
          //得到的result是个迭代对象，需要把它里面的内容转存到数组中
          var nodes = new Array();
          var node;
          while((node = result.iterateNext()) != null) {
              //把迭代器中的内容存到数组中
              nodes.push(node);
          }
          return nodes;
      } else {
          return null;
      }
  } else {
      return null;
  }
}
下面是利用上面的方法查找xml文档中指定条件节点的代码
function testxpath(){
            var rootElement  = loadXML(true,"XPATH.xml");
            removeBlank(rootElement);
            
            //查找所有的author元素节点
            //关键就是如何表式元素节点在DOM树中的路径
            // 绝对路径 /books/book/author
            // 相对路径 book/author
            // 全文档搜索法 //author   //book/author
            var author1 = selectNodes(rootElement,"/books/book/author");
            var author2 = selectNodes(rootElement,"book/author");
            var author3 = selectNodes(rootElement,"//author");
            var author4 = selectNodes(rootElement,"//book/author");
            
            //查找属性节点，查找book节点下isdn属性
            //关键是先找到包含属性节点的元素节点
            var isdn1 = selectNodes(rootElement,"/books/book/@isdn");
            var isdn2 = selectNodes(rootElement,"[email=book/@isdn]book/@isdn[/email]");
            var isdn3 = selectNodes(rootElement,"//book/@isdn");
            var isdn4 = selectNodes(rootElement,"//books/book/@isdn");
            
            //查找文本节点，name元素下面的文本
            //关键是找到包含文本节点的那个元素节点
            var text1 = selectNodes(rootElement,"/books/book/name/text()");
            var text2 = selectNodes(rootElement,"book/name/text()");
            var text3 = selectNodes(rootElement,"//book/name/text()");
            var text4 = selectNodes(rootElement,"//name/text()");
            
            
            //有条件的查找元素节点，包含属性isdn
            //需要首先找到元素节点，然后再增加条件表达式
            var book1 = selectNodes(rootElement,"/books/book[@isdn]");
            var book2 = selectNodes(rootElement,"book[@isdn]");
            var book3 = selectNodes(rootElement,"//book[@isdn]");
            
            //多个条件与关系的查找元素节点
            //需要首先找到元素节点，然后每一个查询条件写在一个中括号中
      var bookA1 = selectNodes(rootElement,"/books/book[@isdn='0002'][price>35]");
      var bookA2 = selectNodes(rootElement,"book[@isdn='0002'][price>35]");
      var bookA3 = selectNodes(rootElement,"//book[@isdn='0002'][price>35]");
            
//多个条件或关系的查找元素节点
//需要首先找到元素节点，然后每一个查询条件写在一个XPATH的表达式，这些表达式用|组合，表式或关系
var bookO1 = selectNodes(rootElement,"/books/book[@isdn='0002'] | /books/book[price>35]");

var bookO2 = selectNodes(rootElement,"book[@isdn='0002'] | /books/book[price>35]");

var bookO3 = selectNodes(rootElement,"//book[@isdn='0002'] | /books/book[price>35]");
}