Java 解析XML的几种方式：DOM、SAX、JDOM和DOM4J。

　　归纳总结Java解析XML主要有四中方式，分别是DOM、SAX、JDOM和DOM4J。其中DOM和SAX是官方包自带，另外两个JDOM和DOM4J是第三方包。

一、此篇测试代码用到的XML情况 。

1、XML内容展示

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <class>
 3     <people>
 4         <name>Jack</name>
 5         <age>19</age>
 6         <sex>male</sex>
 7         <job>student</job>
 8     </people>
 9     <people>
10         <name>Merry</name>
11         <age>26</age>
12         <sex>female</sex>
13         <job>teacher</job>
14     </people>
15 </class>

2、所在项目位置

二、几种方式

1、DOM方式

　　代码及运行结果，已省略类名及main函数代码。

 1 import org.w3c.dom.Document;
 2 import org.w3c.dom.Element;
 3 import org.w3c.dom.Node;
 4 import org.w3c.dom.NodeList;
 5 import org.xml.sax.SAXException;
 6 import javax.xml.parsers.DocumentBuilder;
 7 import javax.xml.parsers.DocumentBuilderFactory;
 8 import javax.xml.parsers.ParserConfigurationException;
 9 import java.io.File;
10 import java.io.IOException;
11 /**
12  * Create by 摩诘 on 2020/4/5 02:00
13  */
14         try {
15             DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
16             DocumentBuilder builder = factory.newDocumentBuilder();
17             String path = HelloWorld.class.getClassLoader().getResource("config/peoples.xml").getPath();
18             File file = new File(path);
19             Document document = builder.parse(file);
20             // 获取节点People集合
21             NodeList nodeList = document.getElementsByTagName("people");
22             for (int i = 0; i < nodeList.getLength(); i++) {
23 //                Element element=(Element) nodeList.item(i);
24 //                NodeList childNodes=element.getChildNodes();
25                 Node node = nodeList.item(i);
26                 NodeList childNodes = node.getChildNodes();
27                 for (int j = 0; j < childNodes.getLength(); j++) {
28                     Node childNode = childNodes.item(j);
29                     if (childNode.getNodeType() == Node.ELEMENT_NODE) {
30                         // 获取节点名称
31                         // 获取对应节点包含的值
32                         System.out.println(childNode.getNodeName() + ":" + childNode.getFirstChild().getNodeValue());
33                     }
34                 }
35                 System.out.println("************************");
36             }
37         } catch (ParserConfigurationException ex) {
38             //ex.printStackTrace();
39             System.out.println("Error : " + ex.toString());
40         } catch (IOException ex) {
41             //ex.printStackTrace();
42             System.out.println("Error : " + ex.toString());
43         } catch (SAXException ex) {
44             //ex.printStackTrace();
45             System.out.println("Error : " + ex.toString());
46         }

2、SAX方式

　　运行效率和内存使用方面最优的是SAX，但是由于SAX是基于事件的方式，所以SAX无法在编写XML的过程中对已编写内容进行修改，但对于不用进行频繁修改的需求，还是应该选择使用SAX。测试代码主要使用到两个类，一个主函数类HelloWorld，一个SAXHandler继承DefaultHandler并重写方法。

 1 import org.xml.sax.helpers.DefaultHandler;
 2 import javax.xml.parsers.SAXParser;
 3 import javax.xml.parsers.SAXParserFactory;
 4 /**
 5  * Create by 摩诘 on 2020/4/5 17:30
 6  */
 7 public class HelloWorld {
 8     public static void main(String[] args) throws Exception{
 9             SAXParserFactory factory=SAXParserFactory.newInstance();
10             SAXParser saxParser=factory.newSAXParser();
11             DefaultHandler handel=new SAXHandler();
12             saxParser.parse("src/config/peoples.xml",handel);
13     }
14 }

 1 import org.xml.sax.Attributes;
 2 import org.xml.sax.SAXException;
 3 import org.xml.sax.helpers.DefaultHandler;
 4 /**
 5  * Create by 摩诘 on 2020/4/5 17:30
 6  */
 7 public class SAXHandler extends DefaultHandler {
 8     @Override
 9     public void startDocument() throws SAXException {
10         super.startDocument();
11         System.out.println("XML解析开始");
12     }
13
14     @Override
15     public void endDocument() throws SAXException {
16         super.endDocument();
17         System.out.println("XML解析结束");
18     }
19
20     @Override
21     public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
22         super.startElement(uri, localName, qName, attributes);
23         if(qName.equals("people")){
24             System.out.println("*************开始遍历poople*************");
25         }else if(!qName.equals("people")&&!qName.equals("class")){
26             System.out.println("节点名称："+qName);
27         }
28     }
29
30     @Override
31     public void endElement(String uri, String localName, String qName) throws SAXException {
32         super.endElement(uri, localName, qName);
33         if(qName.equals("people")){
34             System.out.println(qName+"遍历结束");
35             System.out.println("************结束遍历people**************");
36         }
37     }
38
39     @Override
40     public void characters(char[] ch, int start, int length) throws SAXException {
41         super.characters(ch, start, length);
42         String value=new String(ch,start,length).trim();
43         if(!value.equals("")){
44             System.out.println(value);
45         }
46     }
47 }

3、JDOM方式

　　这种方式为三方包，包地址：https://mvnrepository.com/search?q=jdom，通过构建maven项目引用，maven安装与配置：https://blog.csdn.net/github_37759996/article/details/90748461，创建maven Java程序：https://blog.csdn.net/YF_Li123/article/details/79953731?utm_medium=distribute.pc_relevant.none-task-blog-BlogCommendFromBaidu-1&depth_1-utm_source=distribute.pc_relevant.none-task-blog-BlogCommendFromBaidu-1，上代码。

 1 import org.jdom2.Document;
 2 import org.jdom2.Element;
 3 import org.jdom2.input.SAXBuilder;
 4 import org.jdom2.JDOMException;
 5 import java.io.*;
 6 import java.util.List;
 7
 8 /**
 9  * Create by 摩诘 on 2020/5/2 21:38
10  */
11 public class HelloWorld {
12     public static void main(String[] args) {
13         SAXBuilder saxBuilder=new SAXBuilder();
14         InputStream in;
15         try{
16             in=new FileInputStream(new File("src\\config\\peoples.xml"));
17             Document document=saxBuilder.build(in);
18             Element rootElement=document.getRootElement();
19             List<Element> peopleList=rootElement.getChildren();
20             for (Element people:peopleList){
21                 List<Element> childernList=people.getChildren();
22                 for (Element childern:childernList){
23                     System.out.println("2");
24                     System.out.println(childern.getName()+":"+childern.getValue());
25                 }
26             }
27         }catch(FileNotFoundException e){
28             e.printStackTrace();
29         }catch(JDOMException e){
30             e.printStackTrace();
31         }catch(IOException e){
32             e.printStackTrace();
33         }
34     }
35 }

4、DOM4J

　　三方包，引用方式与JDOM方式类似。看代码

 1 import org.dom4j.Attribute;
 2 import org.dom4j.Document;
 3 import org.dom4j.Element;
 4 import org.dom4j.io.SAXReader;
 5 import java.io.File;
 6 import java.util.Iterator;
 7 import java.util.List;
 8 /**
 9  * Create by 摩诘 on 2020/5/2 22:07
10  */
11 public class HelloWorld {
12     public static void main(String[] args) {
13         SAXReader reader = new SAXReader();
14         try{
15         Document document = reader.read(new File("src/config/peoples.xml"));
16         Element rootElement = document.getRootElement();
17         Iterator iterator = rootElement.elementIterator();
18         while (iterator.hasNext()){
19             Element stu = (Element) iterator.next();
20             List<Attribute> attributes = stu.attributes();
21             System.out.println("======获取属性值======");
22             for (Attribute attribute : attributes) {
23                 System.out.println(attribute.getValue());
24             }
25             System.out.println("======遍历子节点======");
26             Iterator iterator1 = stu.elementIterator();
27             while (iterator1.hasNext()){
28                 Element stuChild = (Element) iterator1.next();
29                 System.out.println("节点名："+stuChild.getName()+"---节点值："+stuChild.getStringValue());
30             }
31          }
32         }catch (Exception e){
33             e.printStackTrace();
34         }
35     }
36 }

三、整理参考了以下链接文章

https://www.jb51.net/article/115316.htm

https://blog.csdn.net/m0_37499059/article/details/80505567