1 需要添加dom4j的jar包https://mvnrepository.com/artifact/dom4j/dom4j

<!-- https://mvnrepository.com/artifact/dom4j/dom4j -->
<dependency>
    <groupId>dom4j</groupId>
    <artifactId>dom4j</artifactId>
    <version>1.6.1</version>
</dependency>

我这里也用到了xpath，所以还得添加jaxen.jar包https://mvnrepository.com/artifact/jaxen/jaxen

<!-- https://mvnrepository.com/artifact/jaxen/jaxen -->
<dependency>
    <groupId>jaxen</groupId>
    <artifactId>jaxen</artifactId>
    <version>1.1.6</version>
</dependency>

2 工具类

package com.xzp.utils;

import java.io.File;
import java.io.FileOutputStream;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;

/**
 * @author xzp
 * @date 2020-07-28 10:51:09
 */
public class XmlUtil {
    /**
     * 将一个xml文件中的节点复制到另一个xml文件
     * @param targetFile 目标文件
     * @param srcFile 源文件（要复制节点所在的文件）
     * @throws Exception
     */
    @SuppressWarnings("unchecked")
    public static void placeSceneCopy(File targetFile, File srcFile) throws Exception {
        XMLWriter writer = null;
        try {
            SAXReader saxReader = new SAXReader();
            Document targetDoc = saxReader.read(targetFile);
            Document otherDoc = saxReader.read(srcFile);
            Element rootElement = targetDoc.getRootElement();
            List<Element> elements = (List<Element>)otherDoc.selectNodes("//krpano/scene");//节点xpath路径
            for(Element element : elements) {
                rootElement.add(element.createCopy());
            }
            OutputFormat format = OutputFormat.createPrettyPrint();
            format.setEncoding("UTF-8");
            writer = new XMLWriter(new FileOutputStream(targetFile), format);
            writer.write(rootElement);
        } finally {
            if(writer != null) writer.close();
        }
    }

}