如何在Java中使用xpath编辑/更新XML文件中的节点
Java代码:如何在Java中使用xpath编辑/更新XML文件中的节点,java,xml,xpath,Java,Xml,Xpath,Java代码: public void update(String id) throws Exception { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = factory.newDocumentBuilder(); Document doc = builder.parse(file_); XPathFactor
public void update(String id) throws Exception
{
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(file_);
XPathFactory xpf = XPathFactory.newInstance();
XPath xpath = xpf.newXPath();
XPathExpression expr = xpath.compile("Servers/server[@ID=" + id + "]");
Node nodeGettingChanged = (Node) expr.evaluate(doc, XPathConstants.NODE);
//HELP START
//? ? ? How do get the node/elements guts to alter that guy
//HELP END
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(doc);
StreamResult result = new StreamResult(file_);
transformer.transform(source, result);
}
之前的XML
<Servers>
<server ID="12234"> // <-- I want to change this node
<name>Greg</name>
<ip>127.0.0.1</ip>
<port>1897</port>
</server>
<server ID="42234">
<name>Bob</name>
<ip>127.0.0.1</ip>
<port>1898</port>
</server>
<server ID="5634">
<name>Tom</name>
<ip>127.0.0.1</ip>
<port>1497</port>
</server>
</Servers>
//您可以尝试以下方法:
NodeList children = nodeGettingChanged.getChildNodes();
chidren.item(0).setNodeValue("SomethingElse");
chidren.item(1).setNodeValue("localHost");
chidren.item(2).setNodeValue("4447");
查看Node#getFirstChild()
和Node#getNextSibling()
以迭代子节点。还请记住,元素之间也存在文本节点,如果不需要,则必须忽略它们。可能不是最有效的代码,但它可以工作(避免使用文本元素)
输出更改的XML片段:
<server ID="12234">
<name>SomethingElse</name>
<ip>localHost</ip>
<port>4447</port>
</server>
某物
本地主机
4447
NodeList childNodes = nodeGettingChanged.getChildNodes();
for (int i = 0; i != childNodes.getLength(); ++i)
{
Node child = childNodes.item(i);
if (!(child instanceof Element))
continue;
if (child.getNodeName().equals("name"))
child.getFirstChild().setNodeValue("SomethingElse") ;
else if (child.getNodeName().equals("ip"))
child.getFirstChild().setNodeValue("localHost") ;
else if (child.getNodeName().equals("port"))
child.getFirstChild().setNodeValue("4447") ;
}
<server ID="12234">
<name>SomethingElse</name>
<ip>localHost</ip>
<port>4447</port>
</server>