java读取xml内容并转换成java对象

可以使用Java中的DOM或SAX解析器来读取XML内容并将其转换为Java对象。

DOM解析器将整个XML文档加载到内存中，允许您对文档进行修改和查询。以下是使用DOM解析器读取XML内容并将其转换为Java对象的示例代码：

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.w3c.dom.Node;
import org.w3c.dom.Element;

public class XmlToObjectConverter {

  public static void main(String[] args) {

    try {
        File inputFile = new File("example.xml");

        DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
        Document doc = dBuilder.parse(inputFile);

        doc.getDocumentElement().normalize();

        NodeList nodeList = doc.getElementsByTagName("student");

        for (int i = 0; i < nodeList.getLength(); i++) {
            Node node = nodeList.item(i);

            if (node.getNodeType() == Node.ELEMENT_NODE) {
                Element element = (Element) node;

                String name = element.getElementsByTagName("name").item(0).getTextContent();
                int age = Integer.parseInt(element.getElementsByTagName("age").item(0).getTextContent());
                String gender = element.getElementsByTagName("gender").item(0).getTextContent();

                Student student = new Student(name, age, gender);
                System.out.println(student);
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
  }
}

class Student {
    private String name;
    private int age;
    private String gender;

    public Student(String name, int age, String gender) {
        this.name = name;
        this.age = age;
        this.gender = gender;
    }

    @Override
    public String toString() {
        return "Name: " + name + ", Age: " + age + ", Gender: " + gender;
    }
}

SAX解析器是一种事件驱动的解析器，它逐行读取XML文档并触发相应的事件。它比DOM解析器更快，但不允许您修改XML文档。以下是使用SAX解析器读取XML内容并将其转换为Java对象的示例代码：

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

public class XmlToObjectConverter {

    public static void main(String[] args) {

        try {
            SAXParserFactory factory = SAXParserFactory.newInstance();
            SAXParser saxParser = factory.newSAXParser();

            DefaultHandler handler = new DefaultHandler() {
                boolean bName = false;
                boolean bAge = false;
                boolean bGender = false;

                public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {

                    if (qName.equalsIgnoreCase("name")) {
                        bName = true;
                    }

                    if (qName.equalsIgnoreCase("age")) {
                        bAge = true;
                    }

                    if (qName.equalsIgnoreCase("gender")) {
                        bGender = true;
                    }
                }

                public void characters(char ch[], int start, int length) throws SAXException {

                    if (bName) {
                        String name = new String(ch, start, length);
                        bName = false;
                    }

                    if (bAge) {
                        int age = Integer.parseInt(new String(ch, start, length));
                        bAge = false;
                    }

                    if (bGender) {
                        String gender = new String(ch, start, length);
                        bGender = false;

                        Student student = new Student(name, age, gender);
                        System.out.println(student);
                    }
                }
            };

            saxParser.parse(new File("example.xml"), handler);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

class Student {
    private String name;
    private int age;
    private String gender;

    public Student(String name, int age, String gender) {
        this.name = name;
        this.age = age;
        this.gender = gender;
    }

    @Override
    public String toString() {
        return "Name: " + name + ", Age: " + age + ", Gender: " + gender;
    }
}