Java如何基于DOM解析xml文件

<?xml version = "1.0" encoding = "UTF-8"?>
<staffs>
  <staff id="1">
    <name>Tom_zhang1</name>
    <age>19</age>
    <sex>男</sex>
    <phone>18677435526</phone>
    <group>
      <id>1</id>
      <name>Technical department</name>
    </group>
  </staff>
  <staff id="2">
    <name>Susy_wang</name>
    <age>18</age>
    <sex>女</sex>
    <phone>18962459987</phone>
    <group>
      <id>2</id>
      <name>Financial department</name>
    </group>
  </staff>
 
  <staff id="3">
    <name>Jack_Ma</name>
    <age>45</age>
    <sex>男</sex>
    <phone>1867755334</phone>
    <group>
      <id>3</id>
      <name>Financial department</name>
    </group>
  </staff>
</staffs>

package Entity;

public class Staff {
  
  private int id;
  private String name;
  private int age;
  private String sex;
  private String phone;
  private StuGroup group;
  public int getId() {
    return id;
  }
  public void setId(int id) {
    this.id = id;
  }
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public int getAge() {
    return age;
  }
  public void setAge(int age) {
    this.age = age;
  }
  public String getSex() {
    return sex;
  }
  public void setSex(String sex) {
    this.sex = sex;
  }
  public String getPhone() {
    return phone;
  }
  public void setPhone(String phone) {
    this.phone = phone;
  }
  public StuGroup getGroup() {
    return group;
  }
  public void setGroup(StuGroup group) {
    this.group = group;
  }
  public Staff() {
    super();
    // TODO Auto-generated constructor stub
  }
  public Staff(int id, String name, int age, String sex, String phone,
      StuGroup group) {
    super();
    this.id = id;
    this.name = name;
    this.age = age;
    this.sex = sex;
    this.phone = phone;
    this.group = group;
  }
  @Override
  public String toString() {
    return "Staff [age=" + age + ", group=" + group + ", id=" + id
        + ", name=" + name + ", phone=" + phone + ", sex=" + sex + "]";
  }
}

package Entity;

public class Group {
  
  private int id;
  private String name;
  public int getId() {
    return id;
  }
  public void setId(int id) {
    this.id = id;
  }
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public Group() {
    super();
    // TODO Auto-generated constructor stub
  }
  public Group(int id, String name) {
    super();
    this.id = id;
    this.name = name;
  }
  @Override
  public String toString() {
    return "Group [id=" + id + ", name=" + name + "]";
  } 
}

package Parser;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

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

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import Entity.StuGroup;
import Entity.Staff;

public class Dom_parser {

  public static List<Staff> parser(String fileName) {

    List<Staff> staffs = new ArrayList<Staff>(); //创建一个ArrayList来装数据

    DocumentBuilderFactory factory = null;  //DocumentBuilderFactory,DocumentBuilder,Document分别是DOM解析的工厂类
    DocumentBuilder builder = null;
    Document doc = null;
    Staff staff = null;           //方便日后实例化
    StuGroup group = null;         //同上

    try {
      factory = DocumentBuilderFactory.newInstance();  //工厂类实例化
      builder = factory.newDocumentBuilder();      //工厂类实例化
      doc = builder.parse(new File(fileName));     //通过.parser方法加载文件

      Element root = doc.getDocumentElement();     //Element方法中的.getDocumentElement()代表获取xml文件的头文件内容

      NodeList nodelist = root.getElementsByTagName("staff"); //获取TagName，每一个<>中的字段为一个TagName.作为一个nodelist来保存
            //循环这个NodeList,然后得到每个nodelist中的item。根据获取到的值的索引最终通过.set方法得到这个值
      for (int index = 0; index < nodelist.getLength(); index++) {
        staff = new Staff();
        Node node = nodelist.item(index);
        staff.setId(Integer.parseInt(node.getAttributes().getNamedItem(
            "id").getTextContent()));
        // System.out.println(staff);

        NodeList childNode = node.getChildNodes();  //设置一个childNode为了存放nodelist下子<>中的TagName
　　　　　　　　　　　　　　　　　　//同上循环子childNode这个list，获取到每个元素的下标。再通过.set方法分别得到每个元素的值。
        for (int i = 0; i < childNode.getLength(); i++) {
          Node childitem = childNode.item(i);
          if (childitem.getNodeName().equals("name")) {
            staff.setName(childitem.getTextContent());
          } else if (childitem.getNodeName().equals("age")) {
            staff.setAge(Integer.parseInt(childitem
                .getTextContent()));
          } else if (childitem.getNodeName().equals("sex")) {
            staff.setSex(childitem.getTextContent());
          } else if (childitem.getNodeName().equals("phone")) {
            staff.setPhone(childitem.getTextContent());
          } else if (childitem.getNodeName().equals("group")) {
            NodeList groupnode = childitem.getChildNodes();

            for (int j = 0; j < groupnode.getLength(); j++) {
              Node groupitem = groupnode.item(j);
                            
              if (groupitem.getNodeName().equals("id")) {
                group = new StuGroup(); //这里的实例化很重要，切记不要实例化错误地方
                String groupId = groupitem.getTextContent();
                group.setId(Integer.parseInt(groupId));
                staff.setGroup(group);
              } else if (groupitem.getNodeName().equals("name")) {
                String groupName = groupitem.getTextContent();
                group.setName(groupName);
                staff.setGroup(group);
              }
            }

          }

        }
        staffs.add(staff); //最终我们要把staff这个对象追加到staffs这个集合中。
      }

    } catch (ParserConfigurationException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (SAXException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
    return staffs; //返回这个集合
  }
}

package Parser;
 
import java.util.List;
 
import Entity.Staff;
 
public class Test {
   
  public static void main(String[] args) {
     
    String file = "C:/Users/IBM_ADMIN/Desktop/xml/staff.xml";  //指定文件地址
    List<Staff> staffs = Dom_parser.parser(file);  //因为我们创建的解析器的名字叫Dom_parser所以在这里调用Dom_parser.parser()方法。（）中参数为文件地址。        //循环并打印结果
    for(Staff list:staffs){
      System.out.println(list);
    }
  }
}