xpath提取xml文档数据

package cn.itcast.sax;


import java.io.File;


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


public class Demo5 {


/**
* 查找user.xml文档是否有和用户相匹配的用户名和密码
* @throws Exception 
*/
public static void main(String[] args) throws Exception {
String username = "aaa";
String password = "123";

//检测xml文档是否有匹配的用户名和密码
SAXReader reader = new SAXReader();
Document document = reader.read(new File("src/user.xml"));

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


}


}