xml合并问题，多个xml拼接

<payment>
    <AuditFileVersion>信息</AuditFileVersion>
    <telephone>销方</telephone>
</payment>

<payment>
    <AuditFileVersion>信息</AuditFileVersion>
    <telephone>销方</telephone>
</payment>

多个上边的xml合并为下边的xml：

<all>
<bb>
<payment>
    <AuditFileVersion>信息</AuditFileVersion>
    <telephone>销方</telephone>
</payment>
<payment>
    <AuditFileVersion>信息</AuditFileVersion>
    <telephone>销方</telephone>
</payment>
</bb>
</all>

实现如下：

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

import java.io.File;
import java.io.FileFilter;
import java.util.List;
import java.util.regex.Pattern;

/**
 * @author Cyhui.
 */
public class aaa {
    public static void main(String[] args) throws Exception {
        SAXReader saxReader = new SAXReader();

        String tube = "F:\\xmll\\root.xml";
        Document rootDoc = saxReader.read(new File(tube));
        Element parent = rootDoc.getRootElement();
        Element flows = parent.element("bb");
        File file = new File("F:\\xmll");
        if (file.exists()) {
            File[] files = file.listFiles(new FileFilter() {
                public boolean accept(File pathname) {
                    String fileName = pathname.getName();
                    String pattern = "^ff.*.xml$";
                    boolean matches = Pattern.matches(pattern, fileName);
                    return matches;
                }
            });
            for (File f : files) {
                Document read = saxReader.read(f);
                List<Element> elements = read.getDocument().getRootElement().elements();
                for (Element emt : elements) {
                    flows.add(emt.detach());
                }
            }
        }
        System.out.println(rootDoc.asXML());
    }
}