Java：如何通过org.w3c.dom.document上的xpath字符串定位元素 [英] Java: how to locate an element via xpath string on org.w3c.dom.document
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问题描述
如何通过指定的org.w3c.dom.document上的xpath字符串快速定位元素/元素？似乎没有 FindElementsByXpath（）方法。例如
How do you quickly locate element/elements via xpath string on a given org.w3c.dom.document? there seems to be no FindElementsByXpath() method. For example
/html/body/p/div[3]/a
我发现，当有很多相同元素的元素时，我会循环遍历所有子节点级别。任何建议？
I found that recursively iterating through all the child node levels to be quite slow when there are lot of elements of same name. Any suggestions?
我不能使用任何解析器或库，只能使用w3c dom文档。
I cannot use any parser or library, must work with w3c dom document only.
推荐答案
尝试这样：
//obtain Document somehow, doesn't matter how
DocumentBuilder b = DocumentBuilderFactory.newInstance().newDocumentBuilder();
org.w3c.dom.Document doc = b.parse(new FileInputStream("page.html"));
//Evaluate XPath against Document itself
XPath xPath = XPathFactory.newInstance().newXPath();
NodeList nodes = (NodeList)xPath.evaluate("/html/body/p/div[3]/a",
doc.getDocumentElement(), XPathConstants.NODESET);
for (int i = 0; i < nodes.getLength(); ++i) {
Element e = (Element) nodes.item(i);
}
使用以下 page.html 文件：
<html>
<head>
</head>
<body>
<p>
<div></div>
<div></div>
<div><a>link</a></div>
</p>
</body>
</html>
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