大家好，又见面了，我是你们的朋友全栈君。

这里写图片描述

xml文件

<?xml version="1.0" encoding="utf-8" ?>
<class>
    <student>
        <firstname>cxx1</firstname>
        <lastname>Bob1</lastname>
        <nickname>stars1</nickname>
        <marks>85</marks>
    </student>
    <student rollno="493">
        <firstname>cxx2</firstname>
        <lastname>Bob2</lastname>
        <nickname>stars2</nickname>
        <marks>85</marks>
    </student>
    <student rollno="593">
        <firstname>cxx3</firstname>
        <lastname>Bob3</lastname>
        <nickname>stars3</nickname>
        <marks>85</marks>
    </student>
</class>

1.DOM方式

package com.cxx.xml;

import org.w3c.dom.*;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
/** * @Author: cxx * Dom操作xml * @Date: 2018/5/29 20:19 */
public class DomDemo { 
   
    //用Element方式
    public static void element(NodeList list){
        for (int i = 0; i <list.getLength() ; i++) {
            Element element = (Element) list.item(i);
            NodeList childNodes = element.getChildNodes();
            for (int j = 0; j <childNodes.getLength() ; j++) {
                if (childNodes.item(j).getNodeType()==Node.ELEMENT_NODE) {
                    //获取节点
                    System.out.print(childNodes.item(j).getNodeName() + ":");
                    //获取节点值
                    System.out.println(childNodes.item(j).getFirstChild().getNodeValue());
                }
            }
        }
    }

    public static void node(NodeList list){
        for (int i = 0; i <list.getLength() ; i++) {
            Node node = list.item(i);
            NodeList childNodes = node.getChildNodes();
            for (int j = 0; j <childNodes.getLength() ; j++) {
                if (childNodes.item(j).getNodeType()==Node.ELEMENT_NODE) {
                    System.out.print(childNodes.item(j).getNodeName() + ":");
                    System.out.println(childNodes.item(j).getFirstChild().getNodeValue());
                }
            }
        }
    }

    public static void main(String[] args) {
        //1.创建DocumentBuilderFactory对象
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        //2.创建DocumentBuilder对象
        try {
            DocumentBuilder builder = factory.newDocumentBuilder();
            Document d = builder.parse("src/main/resources/demo.xml");
            NodeList sList = d.getElementsByTagName("student");
            //element(sList);
            node(sList);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

结果截图

这里写图片描述

2.SAX方式

package com.cxx.xml;
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;

/** * @Author: cxx * SAX解析DOM * 一行一行 Handler * startElement * endElement * @Date: 2018/5/29 20:03 */
public class SaxDemo { 
   

    public static void main(String[] args) throws Exception {
        //1.或去SAXParserFactory实例
        SAXParserFactory factory = SAXParserFactory.newInstance();
        //2.获取SAXparser实例
        SAXParser saxParser = factory.newSAXParser();
        //创建Handel对象
        SAXDemoHandel handel = new SAXDemoHandel();
        saxParser.parse("src/main/resources/demo.xml",handel);
    }
}

class SAXDemoHandel extends DefaultHandler {
    //遍历xml文件开始标签
    @Override
    public void startDocument() throws SAXException {
        super.startDocument();
        System.out.println("sax解析开始");
    }

    //遍历xml文件结束标签
    @Override
    public void endDocument() throws SAXException {
        super.endDocument();
        System.out.println("sax解析结束");
    }

    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        super.startElement(uri, localName, qName, attributes);
        if (qName.equals("student")){
            System.out.println("============开始遍历student=============");
            //System.out.println(attributes.getValue("rollno"));
        }
        else if (!qName.equals("student")&&!qName.equals("class")){
            System.out.print("节点名称:"+qName+"----");
        }
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        super.endElement(uri, localName, qName);
        if (qName.equals("student")){
            System.out.println(qName+"遍历结束");
            System.out.println("============结束遍历student=============");
        }
    }

    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        super.characters(ch, start, length);
        String value = new String(ch,start,length).trim();
        if (!value.equals("")) {
            System.out.println(value);
        }
    }
}

结果截图

这里写图片描述

3.JDOM方式

<!--jdom -->
<dependency>
    <groupId>org.jdom</groupId>
    <artifactId>jdom</artifactId>
    <version>1.1.3</version>
</dependency>

package com.cxx.xml;
import org.jdom.Attribute;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.input.SAXBuilder;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.util.List;
/** * @Author: cxx * JDom解析xml * 快速开发XML应用程序。 * 是一个开源项目 * JDOM主要用来弥补DOM和SAX在实际应用当中的不足。 * @Date: 2018/5/30 11:44 */
public class JDomDemo { 
   
    public static void main(String[] args) throws Exception {
        //1.创建SAXBuilder对象
        SAXBuilder saxBuilder = new SAXBuilder();
        //2.创建输入流
        InputStream is = new FileInputStream(new File("src/main/resources/demo.xml"));
        //3.将输入流加载到build中
        Document document = saxBuilder.build(is);
        //4.获取根节点
        Element rootElement = document.getRootElement();
        //5.获取子节点
        List<Element> children = rootElement.getChildren();
        for (Element child : children) {
            System.out.println("通过rollno获取属性值:"+child.getAttribute("rollno"));
            List<Attribute> attributes = child.getAttributes();
            //打印属性
            for (Attribute attr : attributes) {
                System.out.println(attr.getName()+":"+attr.getValue());
            }
            List<Element> childrenList = child.getChildren();
            System.out.println("======获取子节点-start======");
            for (Element o : childrenList) {
                System.out.println("节点名:"+o.getName()+"---"+"节点值:"+o.getValue());
            }
            System.out.println("======获取子节点-end======");
        }
    }
}

结果截图

这里写图片描述

4.DOM4J方式

 <!-- dom4j -->
 <dependency>
     <groupId>dom4j</groupId>
     <artifactId>dom4j</artifactId>
     <version>1.6.1</version>
</dependency>

package com.cxx.xml;
import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import java.io.File;
import java.util.Iterator;
import java.util.List;

/** * @Author: cxx * Dom4j解析xml * @Date: 2018/5/30 12:21 */
public class Dom4JDemo { 
   
    public static void main(String[] args) throws Exception {
        //1.创建Reader对象
        SAXReader reader = new SAXReader();
        //2.加载xml
        Document document = reader.read(new File("src/main/resources/demo.xml"));
        //3.获取根节点
        Element rootElement = document.getRootElement();
        Iterator iterator = rootElement.elementIterator();
        while (iterator.hasNext()){
            Element stu = (Element) iterator.next();
            List<Attribute> attributes = stu.attributes();
            System.out.println("======获取属性值======");
            for (Attribute attribute : attributes) {
                System.out.println(attribute.getValue());
            }
            System.out.println("======遍历子节点======");
            Iterator iterator1 = stu.elementIterator();
            while (iterator1.hasNext()){
                Element stuChild = (Element) iterator1.next();
                System.out.println("节点名："+stuChild.getName()+"---节点值："+stuChild.getStringValue());
            }
        }
    }
}