public class UnionXml {
public static void union(String xmlFile,String xmlFile2) throws Exception{
SAXBuilder builder = new SAXBuilder();
Document document = builder.build(new File(xmlFile));
Element element = document.getRootElement();
Document document2 = builder.build(new File(xmlFile2));
Element element2 = document2.getRootElement();
Element element3 = (Element) element2.clone();
element.addContent(element3);
XMLOutputter outputter = new XMLOutputter("",true,"GBK");
FileOutputStream out = new FileOutputStream(xmlFile);
outputter.output(document,out);
out.close();
}