如何使用java获取xml节点的属性值 [英] how to get the attribute value of an xml node using java

问题描述

我有一个看起来像这样的xml：

I've an xml which looks like this:

{ <xml><ep><source type="xml">...</source><source type="text">..</source></ep></xml>}

这里我想检索源类型的值，其中类型为s属性。

here i wanna retrieve the value of "source type" where type s an attribute.

我试过这样，但它不起作用：

I 'd tried like this,But its not working:

 DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
                try {
                    DocumentBuilder builder = domFactory.newDocumentBuilder();
                    Document dDoc = builder.parse("D:/workspace1/ereader/src/main/webapp/configurations/config.xml");
                    System.out.println(dDoc);
                    XPath xPath = XPathFactory.newInstance().newXPath();
                    Node node = (Node) xPath.evaluate("//xml/source/@type/text()", dDoc, XPathConstants.NODE);
                    System.out.println(node);
                } catch (Exception e) {
                    e.printStackTrace();

我也试过这个：

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
            DocumentBuilder builder = factory.newDocumentBuilder();
            InputSource is = new InputSource(new StringReader("config.xml"));
            Document doc = builder.parse(is);

            NodeList nodeList = doc.getElementsByTagName("source");

            for (int i = 0; i < nodeList.getLength(); i++) {                
                Node node = nodeList.item(i);

                if (node.hasAttributes()) {
                    Attr attr = (Attr) node.getAttributes().getNamedItem("type");
                    if (attr != null) {
                        String attribute= attr.getValue();                      
                        System.out.println("attribute: " + attribute);                      
                    }
                }
            }

请帮助我!!

提前致谢，
Varsha。

Thanks in advance, Varsha.

推荐答案

你的问题更通用，所以尝试使用Java提供的XML Parsers来实现它。如果您需要特定于解析器，请在此处更新您的代码

Since your question is more generic so try to implement it with XML Parsers available in Java .If you need it in specific to parsers, update your code here what you have tried yet

<?xml version="1.0" encoding="UTF-8"?>
<ep>
    <source type="xml">TEST</source>
    <source type="text"></source>
</ep>

DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse("uri to xmlfile");
XPathFactory xPathfactory = XPathFactory.newInstance();
XPath xpath = xPathfactory.newXPath();
XPathExpression expr = xpath.compile("//ep/source[@type]");
NodeList nl = (NodeList) expr.evaluate(doc, XPathConstants.NODESET);

for (int i = 0; i < nl.getLength(); i++)
{
    Node currentItem = nl.item(i);
    String key = currentItem.getAttributes().getNamedItem("type").getNodeValue();
    System.out.println(key);
}

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