xpath解析xml文档

<?xml version="1.0" encoding="UTF-8"?>
<user>
<user id="1" username="aaa" password="123">李</user>
<user id="2" username="bbb" passwoed="456">王</user>
<user id="3" username="ccc" password="789">刘</user>
</user>

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

public class XpathExample{

public static void main(String[] args) throws Exception {
String username="aaa";
String password="123";

SAXReader reader=new SAXReader();
Document document=reader.read("src/User.xml");

/*//获得单个节点
String value=document.selectSingleNode("user/a").getText();
System.out.println(value);*/

Node node=document.selectSingleNode("//user[@username='"+username+"' and @password='"+password+"']");
if(node==null){
System.out.println("用户名或者密码错误！！！");
}
else System.out.println("成功登录");
}
}