java----DOM解析XML

 DOM：

直接一次性将XML文件读取到内存中，所以可以跨节点读取所需要的数据

适合服务器开发

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import javax.xml.parsers.*;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

public class Demo{
    public static void main(String[] args) throws IOException, SAXException, ParserConfigurationException {
        xmlTest();
    }
    public static void xmlTest() throws ParserConfigurationException, SAXException, IOException {
        //创建一个DOM解析器工厂对象;
        DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
        //通过工厂对象创建DOM解析器
        DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
        //解析文档
        InputStream resourceAsStream = Thread.currentThread().getContextClassLoader().getResourceAsStream("com\\first\\person.xml");
        Document doc = documentBuilder.parse(resourceAsStream);//doc 即为树状结构的存储对象,在内存中;

        ArrayList<Person> personList = new ArrayList<>();
        NodeList XMLpersonlist = doc.getElementsByTagName("person");
        Person person = null;
        for (int i = 0; i <XMLpersonlist.getLength(); i++) {
            person = new Person();
            //获取属性值
            String p_id = XMLpersonlist.item(i).getAttributes().getNamedItem("person_id").getNodeValue();
            person.setId(p_id);
            NodeList childNodes = XMLpersonlist.item(i).getChildNodes();
            for (int j = 0; j < childNodes.getLength(); j++) {
                Node children_node = childNodes.item(j);
                String node_name = children_node.getNodeName();
                if ("name".equals(node_name)){
                    //把文本也看成一个节点，<name>zy</name> 中zy当做节点；children_node.getFirstChild()表示获取zy这个节点；
                    //zy.getNodeValue() 获取的值就是zy;
                    String p_name = children_node.getFirstChild().getNodeValue();
                    person.setName(p_name);
                }else if ("age".equals(node_name)){
                    String p_age = children_node.getFirstChild().getNodeValue();
                    person.setAge(p_age);
                }
            }
            personList.add(person);
        }
        personList.forEach((p)->System.out.println(p));
    }
}

class Person{
    private String name;
    private String age;
    private String id;
    public void setName(String name) {
        this.name = name;
    }
    public void setAge(String age) {
        this.age = age;
    }
    public void setId(String id) {
        this.id = id;
    }
    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age='" + age + '\'' +
                ", id='" + id + '\'' +
                '}';
    }
}

　

XML文件

<?xml version="1.0" encoding="UTF-8" ?>
<Person>
    <person person_id="p1">
        <name>zy</name>
        <age>18</age>
    </person>
    <person person_id="p2">
        <name>zt</name>
        <age>20</age>
    </person>
</Person>