Java HTML/XML - 如何使用XML中的相应属性值获取值的计数

import java.io.File;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

public class Main {
  public static void main(String[] args) throws Exception{
    List<Car> carsList = new ArrayList<Car>();
    Set<Car> carsset = new HashSet<Car>();
    File fXmlFile = new File("cars.xml");
    DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
    DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
    Document doc = dBuilder.parse(fXmlFile);
    doc.getDocumentElement().normalize();
    NodeList nList = doc.getElementsByTagName("cars");
    Car tempCar = null;
    for (int temp = 0; temp < nList.getLength(); temp++) {
      Node nNode = nList.item(temp);
      if (nNode.getNodeType() == Node.ELEMENT_NODE) {
        tempCar = new Car();
        Element eElement = (Element) nNode;
        tempCar.setModel(eElement.getElementsByTagName("model").item(0)
            .getTextContent());
        tempCar.setVersion(eElement.getElementsByTagName("version").item(0)
            .getTextContent());
        carsList.add(tempCar);
        carsset.add(tempCar);

      }
    }
    for (Car cs : carsset) {
      int count = 0;
      for (Car cl : carsList) {
        if (cs.equals(cl)) {
          count = count + 1;
        }
      }
      System.out.println(cs + "\t" + count);
    }
  }
}

class Car {
  private String model;
  private String version;

  public String getModel() {
    return model;
  }

  public void setModel(String model) {
    this.model = model;
  }

  public String getVersion() {
    return version;
  }

  public void setVersion(String version) {
    this.version = version;
  }

  @Override
  public boolean equals(Object obj) {
    if (this.model.equals(((Car) obj).getModel())
        && this.version.equals(((Car) obj).getVersion())) {
      return true;
    }
    return false;
  }

  @Override
  public int hashCode() {
    return this.model.length() + this.version.length();
  }

  @Override
  public String toString() {
    return this.model + "\t " + this.version;
  }
}