XML DOM解析XML文件-蒲公英云

采用DOM解析student.xml文件，将解析的每组数据保存在Student对象中，然后将Student对象添加到List集合。

注：解析器读入整个文档，然后构建一个驻留内存的树结构，使用 DOM 接口来操作这个树结构。

一、解析的XML文件（student.xml）

<?xml version="1.0" encoding="utf-8" ?><!--xml文档声明-->
<!--DTD约束-->
<!DOCTYPE class [
        <!ELEMENT student (name,age,sex,height)>
        <!ELEMENT name (#PCDATA)>
        <!ELEMENT age (#PCDATA)>
        <!ELEMENT sex (#PCDATA)>
        <!ELEMENT height (#PCDATA)>
        ]>
<!--只能有一个根标签-->
<class>
    <!--设置属性-->
    <student id="1" user="lisi">
        <name>李四</name>
        <age>18</age>
        <sex>男</sex>
        <height>182</height>
    </student>
    <student id="2" user="wangwu">
        <name>王五</name>
        <age>19</age>
        <sex>男</sex>
        <height>172</height>
    </student>
</class>

二、解析代码

package com.xml.main;
import org.w3c.dom.*;
import org.xml.sax.SAXException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
public class DOMParseMain {
    public static void main(String[] args) {
        try {
//            使用List存储解析到的学生信息
            ArrayList<Student> list = new ArrayList<>();
            //DOM解析的步骤
            //步骤一：创建DOM解析工厂
            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
            //步骤二：通过解析工厂 创建一个XML文档解析者
            DocumentBuilder documentBuilder = factory.newDocumentBuilder();
            //步骤三： 解析指定XML文件
            Document document = documentBuilder.parse(new File("student.xml"));
            //开始解析
            Element documentElement = document.getDocumentElement();
            //获取根元素节点下所有的节点(包含此节点的所有子节点，如：元素节点，文本节点，注释节点，空格换行等)
            NodeList childNodes = documentElement.getChildNodes();
            for (int i = 0; i < childNodes.getLength(); i++) {
                Node item = childNodes.item(i);
                Student student = new Student();
//                只获取元素节点并且节点名称为student
                if (item.getNodeType() == Node.ELEMENT_NODE && "student".equals(item.getNodeName())) {
                    NamedNodeMap attributes = item.getAttributes();//得到Student所有的属性
                    Node id = attributes.getNamedItem("id");//获取id节点
                    String idValue = id.getNodeValue();//获取id的属性值
                    Node user = attributes.getNamedItem("user");//获取user节点
                    String userValue = user.getNodeValue();//获取user 属性值
                    //添加信息到student对象中
                    student.setId(Integer.parseInt(idValue));
                    student.setUser(userValue);
                    //遍历student节点下面的子节点
                    NodeList childNodes1 = item.getChildNodes();
                    for (int j = 0; j < childNodes1.getLength(); j++) {
                        Node item1 = childNodes1.item(j);
//                        获取元素节点
                        if (item1.getNodeType() == Node.ELEMENT_NODE) {
                            switch (item1.getNodeName()) {
                                case "name":
                                    String nameValue = item1.getFirstChild().getNodeValue();
                                    student.setName(nameValue);
                                    break;
                                case "height":
                                    String heightValue = item1.getFirstChild().getNodeValue();
                                    student.setHeight(Double.parseDouble(heightValue));
                                    break;
                                case "age":
                                    String ageValue = item1.getFirstChild().getNodeValue();
                                    student.setAge(Integer.parseInt(ageValue));
                                    break;
                                case "sex":
                                    String sexValue = item1.getFirstChild().getNodeValue();
                                    student.setSex(sexValue);
                                    break;
                            }
                        }
                    }
                    list.add(student);
                }
            }
//遍历List
            for (Student s : list) {
                System.out.println(s.toString());
            }
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
        }
    }
}

三、Student.java

package com.xml.main;
public class Student {
    private int id;
    private String user;
    private String name;
    private String sex;
    private int age;
    private double height;
    public Student() {
    }
    public Student(int id, String user, String name, String sex, int age, double height) {
        this.id = id;
        this.user = user;
        this.name = name;
        this.sex = sex;
        this.age = age;
        this.height = height;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getUser() {
        return user;
    }
    public void setUser(String user) {
        this.user = user;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public double getHeight() {
        return height;
    }
    public void setHeight(double height) {
        this.height = height;
    }
    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", user='" + user + '\'' +
                ", name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                ", age=" + age +
                ", height=" + height +
                '}';
    }
}