不是很明白
就举个例子吧
<root>
 <xml>1</xml>
 <node>
  <xml>2</xml>
  <AAA>
   <xml>3</xml>
  </AAA>
 </node>
</root>
从node搜索的话，这三种方法分别能搜到1、2、3中的哪几个？

nodename  选取此节点的所有子节点
/  从根节点选取
//  从匹配选择的当前节点选择文档中的节点，而不考虑它们的位置

参考资料：http://www.w3school.com.cn/xpath/xpath_syntax.asp

import java.io.FileWriter;

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

public class CreateDom4j {
 public static String createXml() throws Exception{
  Document document=DocumentHelper.createDocument();
  Element root=document.addElement("lee");
  Element country=root.addElement("abin");
  Element area=country.addElement("name");
  Element first=area.addElement("lc1");
  first.addText("lc1name");
  Element middle=area.addElement("lc2");
  middle.addText("lc2name");
  Element last=area.addElement("lc3");
  last.addText("lc3name");
  
  FileWriter fileWriter=new FileWriter("lbin.xml");
  OutputFormat format=new OutputFormat();
  format.setEncoding("UTF-8");
  XMLWriter writer=new XMLWriter(fileWriter, format);
  writer.write(document);
  writer.flush();
  writer.close();
  return document.asXML();
 }
 public static void main(String[] args)throws Exception {
  String result=createXml();
  System.out.println("result="+result);
 }
}

生成的XML文件内容
<?xml version="1.0" encoding="UTF-8"?>
<lee><abin><name><lc1>lc1name</lc1><lc2>lc2name</lc2><lc3>lc3name</lc3></name></abin></lee>





//DOM4J解析XML文件

package lc.abin.lee.xml.dom4j;

import java.io.File;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

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

public class ParseJdom {
 public static Map<String,String> parse(File file) throws DocumentException{
  Map<String,String> map=Collections.synchronizedMap(new HashMap<String,String>());
  SAXReader sax=new SAXReader();
  Document doc=sax.read(file);
  List list=doc.selectNodes("/lee/abin/name");
  for(Iterator it=list.iterator();it.hasNext();){
   Element ele=(Element)it.next();
   for(Iterator its=ele.elementIterator();its.hasNext();){
    Element le=(Element)its.next();
    map.put(le.getName(), le.getText());
    System.out.println("le.getName()="+le.getName());
    System.out.println("le.getText()="+le.getText());
   }
   
  }
  return map;
 }
 public static void main(String[] args) throws Exception {
  File file=new File("lbin.xml");
  Map<String,String> map=parse(file);
  for(Iterator it=map.entrySet().iterator();it.hasNext();){
   Map.Entry entry=(Map.Entry)it.next();
   System.out.println("name="+entry.getKey());
   System.out.println("value="+entry.getValue());
   
  }
 }

}

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;

public class CreateDom4j {
 public static String createXml(){
  Document document=DocumentHelper.createDocument();
  Element school=document.addElement("school");
  Element teacher=school.addElement("teacher");
  Element student=teacher.addElement("student");
  student.addText("abin");
  Element boy=teacher.addElement("boy");
  boy.addText("han");
  Element girl=teacher.addElement("girl");
  girl.addText("xia");
  
  return document.asXML();
 }
 
 public static Map<String, String> parseXml(String xml){
  Map<String, String> map=new HashMap<String, String>();
  Document doc=null;
  try {
   doc=DocumentHelper.parseText(xml);
   Element school=doc.getRootElement();
   System.out.println("school Name="+school.getName());
   System.out.println("school Value="+school.getText());
   map.put(school.getName(), school.getText());
   
   Element teacher=school.element("teacher");
   map.put(teacher.getName(), teacher.getText());
   
   Element student=teacher.element("student");
   map.put(student.getName(), student.getText());
   
   Element boy=teacher.element("boy");
   map.put(boy.getName(), boy.getText());
   
   Element girl=teacher.element("girl");
   map.put(girl.getName(), girl.getText());
  } catch (Exception e) {
   e.printStackTrace();
  }
  return map;
 }
 
 public static Map<String, String> parseString(String xml){
  Map<String, String> map=new HashMap<String, String>();
  Document doc=null;
  try {
   doc=DocumentHelper.parseText(xml);
   Element school=doc.getRootElement();
   map.put(school.getName(), school.getText());
   
   Element teacher=school.element("teacher");
   map.put(teacher.getName(), teacher.getText());
   
   for(Iterator it=teacher.elementIterator();it.hasNext();){
    Element element=(Element)it.next();
    map.put(element.getName(), element.getText());
   }
  } catch (Exception e) {
   e.printStackTrace();
  }
  return map;
 }
 public static void main(String[] args) {
  String result=createXml();
  System.out.println("result="+result);
//  Map<String, String> map=parseXml(result);
//  for(Iterator it=map.entrySet().iterator();it.hasNext();){
//   Map.Entry entry=(Map.Entry)it.next();
//   System.out.println("entry name="+entry.getKey());
//   System.out.println("entry value="+entry.getValue());
//  }
  
  Map<String, String> map=parseString(result);
  for(Iterator it=map.entrySet().iterator();it.hasNext();){
   Map.Entry entry=(Map.Entry)it.next();
   System.out.println("entry name="+entry.getKey());
   System.out.println("entry value="+entry.getValue());
  }
  
  
 }

}


http://hi.baidu.com/stevenjohn/item/aababd47077c0ce5dd0f6c78

import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;

public class Dom4jCreate {
 public static String CreateXml(){
  Document document=DocumentHelper.createDocument();
  document.setXMLEncoding("UTF-8");
  Element rootElement=document.addElement("abin").addAttribute("version", "1.01");
  Element first=rootElement.addElement("header").addAttribute("type", "input");
  Element second=first.addElement("one").addText("中国");
  
  return document.asXML();
 }
 public static void main(String[] args) {
  Dom4jCreate dom4jC=new Dom4jCreate();
  String result=dom4jC.CreateXml();
  System.out.println("result="+result);
 }

}