使用 XPath Java 设置节点值 [英] Setting node value using XPath Java

问题描述

我正在尝试通过 XPath 设置节点值.我有以下内容，但它似乎没有改变实际的文件值.

I'm trying to set a node value via an XPath. I have the following but it doesn't seem to change the actual files value.

XPathFactory factory = XPathFactory.newInstance();
XPath xPath = factory.newXPath();

xPathExpression = "//test";
xPathValue= "111";

NodeList nodes = (NodeList) xPath.evaluate(xPathExpression, new InputSource(new FileReader(fileName)), XPathConstants.NODESET);

for (int k = 0; i < nodes.getLength(); i++)
{
    System.out.println(nodes.item(k).getTextContent());  // Prints original value
    nodes.item(k).setTextContent(xPathValue);
    System.out.println(nodes.item(k).getTextContent());  // Prints 111 after
}

但该节点的文件内容保持不变.

But file contents for that node remain unchanged.

如何设置那个节点的值?

How do I set the value of that node?

谢谢

推荐答案

您只是在更改内存中的值，而不是文件本身.您需要将修改后的文档写回到文件中:

You're merely changing the value in memory, not in the file itself. You need to write the modified document back out to the file:

Source source = new DOMSource(doc);
Result result = new StreamResult(new File(fileName));
Transformer xformer;
try {
    xformer = TransformerFactory.newInstance().newTransformer();
    xformer.transform(source, result);
} catch (TransformerConfigurationException e) {
    // TODO Auto-generated catch block
} catch (TransformerFactoryConfigurationError e) {
    // TODO Auto-generated catch block
} catch (TransformerException e) {
    // TODO Auto-generated catch block
}

这些类都来自javax.xml.transform.*.

(当然，您需要保存对文档的引用，以便您可以写回它(即，您将无法继续将其直接传递给 evaluate)).

(You'll need to save a reference to the document, of course, so that you can write back to it (i.e. you won't be able to continue passing it directly into evaluate)).

这篇关于使用 XPath Java 设置节点值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！