получить элемент по ID с помощью DOM парсер в JAVA для другой структуры XML

Question

У меня есть файл XML, который структурирован так:

<Users> 
<user id="1" groupid="G1" username="GON"/> 
<user id="2" groupid="G2" username="NARUTO"/> 
<user id="3" groupid="G3" username="GOKU"/> 
</Users> 

Мне нужно значение GetAttribute из GroupID и имя пользователя

На данный момент мой JAVA CODE;

Document doc = db.parse(is); 
NodeList nodes = doc.getElementsByTagName("Users"); 
for (int i = 0; i < nodes.getLength(); i++) { 
    Element element = (Element) nodes.item(i);   
    NodeList Users = element.getElementsByTagName("User"); 
    for (int temp = 0; temp < Users.getLength(); temp++) { 
     Node nNode = Users.item(temp);          
     System.out.println("\nCurrent Element :" + nNode.getNodeName()); 
     if (nNode.getNodeType() == Node.ELEMENT_NODE) { 
      Element eElement = (Element) nNode; 
      System.out.println("Staff username : " + eElement.getAttribute("username")); 
     } 
    }  
} 

Answer 1

вы можете использовать XStream, чтобы это сделать, и написать свой собственный конвертер:

import com.thoughtworks.xstream.XStream; 
import com.thoughtworks.xstream.annotations.XStreamAlias; 
import com.thoughtworks.xstream.converters.Converter; 
import com.thoughtworks.xstream.converters.MarshallingContext; 
import com.thoughtworks.xstream.converters.UnmarshallingContext; 
import com.thoughtworks.xstream.io.HierarchicalStreamReader; 
import com.thoughtworks.xstream.io.HierarchicalStreamWriter; 
import com.thoughtworks.xstream.io.xml.DomDriver; 

import javax.xml.bind.JAXBException; 
import java.io.FileNotFoundException; 
import java.util.ArrayList; 
import java.util.List; 

/** 
* @author heyunxia (love3400wind@163.com) 
* @version 1.0 
* @since 2016-01-15 上午11:21 
*/ 
public class Xml2Bean { 

    public static void main(String[] args) throws JAXBException, FileNotFoundException { 

     XStream xstream = new XStream(new DomDriver()); 
     xstream.registerConverter(new UserCoverter()); 
     xstream.processAnnotations(User.class); 
     xstream.addImplicitCollection(Users.class, "list"); 
     xstream.autodetectAnnotations(true); 


     List<User> list = new ArrayList<>(); 
     list.add(new User("1", "G1", "GON")); 
     list.add(new User("2", "G2", "NARUTO")); 
     list.add(new User("3", "G3", "GOKU")); 
     Users users = new Users(list); 

     String xml = xstream.toXML(users); 
     System.out.println(xml); 

     Users usersFile = (Users) xstream.fromXML(xml); 
     System.out.printf(usersFile.toString()); 
    } 
} 

class UserCoverter implements Converter { 

    @Override 
    public void marshal(Object source, HierarchicalStreamWriter writer, MarshallingContext context) { 
     User user = (User) source; 
     writer.addAttribute("id", user.getId()); 
     writer.addAttribute("groupid", user.getGroupid()); 
     writer.addAttribute("username", user.getUsername()); 

    } 

    @Override 
    public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) { 
     User user = new User(); 
     user.setId(reader.getAttribute("id")); 
     user.setGroupid(reader.getAttribute("groupid")); 
     user.setUsername(reader.getAttribute("username")); 
     return user; 
    } 

    @Override 
    public boolean canConvert(Class type) { 
     return type.equals(User.class); 
    } 
} 

@XStreamAlias("Users") 
class Users { 
    private List<User> list; 

    public Users(List<User> list) { 
     this.list = list; 
    } 
} 


@XStreamAlias("user") 
class User { 
    @XStreamAlias("id") 
    private String id; 
    private String groupid; 
    private String username; 

    public User() { 
    } 

    public User(String id, String groupid, String username) { 
     this.id = id; 
     this.groupid = groupid; 
     this.username = username; 
    } 

    public String getId() { 
     return id; 
    } 

    public void setId(String id) { 
     this.id = id; 
    } 

    public String getGroupid() { 
     return groupid; 
    } 

    public void setGroupid(String groupid) { 
     this.groupid = groupid; 
    } 

    public String getUsername() { 
     return username; 
    } 

    public void setUsername(String username) { 
     this.username = username; 
    } 
}