如何在java中的某个元素之后/之前将元素插入到xml中

import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;

File inputFile = new File("input.xml");
DocumentBuilderFactory documentFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder documentBuilder = documentFactory.newDocumentBuilder();
Document document = documentBuilder.parse(inputFile);

// 查找要插入新元素的位置
Element existingElement = document.getElementById("existingElementId");

// 创建新元素
Element newElement = document.createElement("newElement");
newElement.setTextContent("New Element Content");

// 在现有元素之前插入新元素
Node parent = existingElement.getParentNode();
parent.insertBefore(newElement, existingElement);

// 或者在现有元素之后插入新元素
Node nextSibling = existingElement.getNextSibling();
if (nextSibling == null) {
    parent.appendChild(newElement);
} else {
    parent.insertBefore(newElement, nextSibling);
}

TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
DOMSource source = new DOMSource(document);
StreamResult result = new StreamResult(new File("output.xml"));
transformer.transform(source, result);