First create an xml document, the content of the document is as follows

<?xml version="1.0" encoding="UTF-8"?>
<bookstore>
	<book id="1">
		 <name>Programming Beauty</name>
		<price>34.0</price>
		 <author> "The Beauty of Programming" group</author>
	</book>
	<book id="2">
		 <name>Ordinary World</name>
		<price>56.0</price>
		 <author> </author>
		 <language> </language>
	</book>
</bookstore>

Because the xml definition is the book's book details, after parsing the xml, I want to save the parsed data, so I define a Book Entity and define each attribute

package com.ikok.parsexml;

public class Book {
	private String id;
	private String name;
	private String price;
	private String author;
	private String language;
	
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPrice() {
		return price;
	}
	public void setPrice(String price) {
		this.price = price;
	}
	public String getAuthor() {
		return author;
	}
	public void setAuthor(String author) {
		this.author = author;
	}
	public String getLanguage() {
		return language;
	}
	public void setLanguage(String language) {
		this.language = language;
	}
	
}

DOM parsing:

package com.ikok.parsexml;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class domXml {
	
	private static List<Book> booksList = new ArrayList<Book>();
	
	public static void main(String[] args) {
		// Create a DocumentBuilderFactory object
		DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
		try {
			 // Create a DocumentBuilder object
			DocumentBuilder db = dbf.newDocumentBuilder();
			 // Load the xml file into the current project via the parse method of the DocumentBuilder object
			Document document = db.parse("books.xml");
			 / / Get a collection of all book nodes
			NodeList bookList = document.getElementsByTagName("book");
			 // Traverse each book node and know the length of the collection via the bookList.getLength() method
			 System.out.println("a total" + bookList.getLength() + "book");
			for (int i = 0; i < bookList.getLength(); i++) {
				Book bookItem = new Book();
				 System.out.println("----------- Start traversing the first" + (i+1) + "The contents of this book ---------");
				 // Get a book node by the item(i) method, the index value of the NodeList starts from 0
				Node book = bookList.item(i);
				 / / Get all the property collection of the book node
				NamedNodeMap attrs = book.getAttributes();
				 System.out.println(" " + (i+1) + "This book has " + attrs.getLength() + " attributes");
				 // traverse the properties of the book
				for (int j = 0; j < attrs.getLength(); j++) {
					 // Get a property of a book node by the item(i) method
					Node attr = attrs.item(j);
					 / / Get the property name
					 System.out.print("property name:" + attr.getNodeName());
					 / / Get the attribute value
					 System.out.println("----property value:" + attr.getNodeValue());
					if(attr.getNodeName().equals("id")){
						bookItem.setId(attr.getNodeValue());
					}
				}
				
				 // When you know that a node has one and only one attribute, perform a cast, and get the attribute value via the getAttribute() method.
//				Element book = (Element) bookList.item(i);
//				String attrValue = book.getAttribute("id");
//				System.out.println("id ：" + attrValue);
				
				 / / Analyze the child nodes of the book node
				NodeList childList = book.getChildNodes();
				 System.out.println(" " + (i+1) + "This book has " + childList.getLength() + " child nodes");
				for (int k = 0; k < childList.getLength(); k++) {
					 / / Distinguish between node type of text type and element type node
					if (childList.item(k).getNodeType() == Node.ELEMENT_NODE) {
						 / / Get the node name of the element type node
						 System.out.print(" " + (i+1) + " The child node name of the book: " + childList.item(k).getNodeName() + "----");
						 // If there are still nodes in the current node, the attribute value is null. For example, <name><a>aa</a><b>bb</b> first line of code</name>
						 System.out.println(" Property Value: " + childList.item(k).getFirstChild().getNodeValue());
						 // This will output the contents of all child nodes and nodes. Will output the first line of aabb code
//						System.out.println(childList.item(k).getTextContent());
						if(childList.item(k).getNodeName().equals("name")){
							bookItem.setName(childList.item(k).getFirstChild().getNodeValue());
						} else if(childList.item(k).getNodeName().equals("price")){
							bookItem.setPrice(childList.item(k).getFirstChild().getNodeValue());
						} else if(childList.item(k).getNodeName().equals("author")){
							bookItem.setAuthor(childList.item(k).getFirstChild().getNodeValue());
						} else if(childList.item(k).getNodeName().equals("language")){
							bookItem.setLanguage(childList.item(k).getFirstChild().getNodeValue());
						}
					}
				}
				
				 System.out.println("-----------End traversal" + (i+1) + "Content of the book -----------");
				System.out.println();
				booksList.add(bookItem);
				bookItem = null;
			}
			for (Book item : booksList) {
				 System.out.println("book id :" + item.getId());
				 System.out.println("book name:" + item.getName());
				 System.out.println("book price:" + item.getPrice());
				 System.out.println("book author :" + item.getAuthor());
				 System.out.println("book language :" + item.getLanguage());
				System.out.println("---------------------------------");
			}
		} catch (ParserConfigurationException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SAXException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	
}

Result:

A total of 2 books
 ----------- Begin to traverse the contents of the first book -----------
 Book 1 has 1 attribute
 The attribute name is: id----The attribute value is: 1
 Book 1 has 7 sub-nodes
 The name of the child of the first book: name---- Attribute value: the beauty of programming
 Subnode name of Book 1: price---- Attribute value: 34.0
 The name of the child of the first book: author---- Attribute value: "The beauty of programming" group
 ----------- End the traversal of the contents of the first book -----------

 ----------- Begin to traverse the contents of the second book -----------
 Book 2 has 1 attribute
 The property name is: id----The attribute value is: 2
 Book 2 has 9 child nodes
 Subnode name of Book 2: name---- Attribute value: Ordinary world
 Subnode name of Book 2: price---- Attribute value: 56.0
Subnode name of Book 2: author---- Attribute value: Lu Yao
 Subnode name of Book 2: language---- Attribute value: Chinese
 ----------- End the traversal of the contents of the second book -----------

 Book id :1
 Book name: the beauty of programming
 Book price: 34.0
 Book author: "The Beauty of Programming" group
 Book language :null
---------------------------------
 Book id : 2
 Book name: ordinary world
 Book price: 56.0
 Book author: Lu Yao
 Book language : Chinese
---------------------------------

SAX parsing:

package com.ikok.parsexml;

import java.io.IOException;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.SAXException;

public class SAXXml {
	
	public static void main(String[] args) {
		 // Create an instance of SAXParserFactory
		SAXParserFactory saxpf = SAXParserFactory.newInstance();
		try {
			 // Get an instance of SAXParser from an instance of SAXParserFactory
			SAXParser parser = saxpf.newSAXParser();
			SAXParserHandler handler = new SAXParserHandler();
			parser.parse("books.xml", handler);
			 System.out.println("Total" + handler.getBookList().size() + "Book");
			for (Book book : handler.getBookList()) {
				 System.out.println("book id :" + book.getId());
				 System.out.println("book name:" + book.getName());
				 System.out.println("book price:" + book.getPrice());
				 System.out.println("Book Author:" + book.getAuthor());
				 System.out.println("book language :" + book.getLanguage());
				System.out.println("---------------------------------");
			}
		} catch (ParserConfigurationException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SAXException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

Because the SAX parsing xml parsing method requires a DefaultHandler parameter, I defined a SAXParserHandler to inherit this class, rewriting some methods

package com.ikok.parsexml;

import java.util.ArrayList;
import java.util.List;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

public class SAXParserHandler extends DefaultHandler {
	
	 // The serial number of the book
	int bookIndex = 0;
	/**
	  * An attribute value
	  * Because the property name is obtained in the startElement() method, but the property value is obtained in the characters() method.
	  * In order to add the attribute name and attribute value to the book instance, the other two methods are executed before the endElement() method, so it is processed here.
	 */
	String value = null;
	Book book = null;
	private List<Book> bookList = new ArrayList<Book>();
	
	public List<Book> getBookList() {
		return bookList;
	}


	 / / used to traverse the start tag of the xml file
	@Override
	public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
		super.startElement(uri, localName, qName, attributes);
		 // Start parsing the attributes of the book element
		if(qName.equals("book")){
			 // Create a book object
			book = new Book();
			bookIndex++;
			System.out.println("----------- Start traversing the first" + bookIndex + "The contents of the book -----------");
 // // Know the name of the attribute under the book element, get the attribute value based on the attribute name
//			String value = attributes.getValue("id");
//			System.out.println("id:" + value);
			 / / Do not know the name and number of attributes under the book element, get the attribute name and attribute value
			 // number of attributes
			int num = attributes.getLength();
			for (int i = 0; i < num; i++) {
				 System.out.print(" " + (i+1) + "Attribute Name: " + attributes.getQName(i));
				 System.out.println(" Attribute Value: " + attributes.getValue(i));
				if (attributes.getQName(i).equals("id")) {
					book.setId(attributes.getValue(i));
				}
			}
		} else if(!qName.equals("book") && !qName.equals("bookstore")){
			 System.out.print("node name:" + qName + "node value:");
		}
	};
	
	 / / used to traverse the end tag of the xml file
	@Override
	public void endElement(String uri, String localName, String qName) throws SAXException {
		super.endElement(uri, localName, qName);
		 // Whether the content of a book ends in traversal
		if (qName.equals("book")) {
			 // empty the book to facilitate the next one
			bookList.add(book);
			book = null;
			 System.out.println("-----------End traversal" + bookIndex + "Content of the book -----------");
		} else if(qName.equals("name")){
			book.setName(value);
		} else if(qName.equals("price")){
			book.setPrice(value);
		} else if(qName.equals("author")){
			book.setAuthor(value);
		} else if(qName.equals("language")){
			book.setLanguage(value);
		}
		
	};
	
	 / / used to mark the beginning of parsing
	@Override
	public void startDocument() throws SAXException {
		// TODO Auto-generated method stub
		super.startDocument();
		 System.out.println("SAX parsing starts");
	}
	
	 / / used to mark the end of parsing
	@Override
	public void endDocument() throws SAXException {
		// TODO Auto-generated method stub
		super.endDocument();
		 System.out.println("SAX parsing ends");
	}
	
	@Override
	public void characters(char[] ch, int start, int length) throws SAXException {
		// TODO Auto-generated method stub
		super.characters(ch, start, length);
		 / / Get the attribute value
		value = new String(ch, start, length);
		 // By default, the newline in xml will be counted, the output format is incorrect, and the newline is removed.
		if (!value.trim().equals("")) {
			System.out.println(value);
		}
	}
	
	
	
	
}

Result:

SAX analysis begins
 ----------- Begin to traverse the contents of the first book -----------
 The first attribute name: id attribute value: 1
 Node name: name Node value: the beauty of programming
 Node name: price node value: 34.0
 Node name: author node value: "Programming Beauty" group
 ----------- End the traversal of the contents of the first book -----------
 ----------- Begin to traverse the contents of the second book -----------
 First attribute name: id attribute value: 2
 Node name: name Node value: ordinary world
 Node name: price node value: 56.0
 Node name: author node value: Lu Yao
 Node name: language node value: Chinese
 ----------- End the traversal of the contents of the second book -----------
 End of SAX parsing
 2 books in total
 Book id :1
 Book name: the beauty of programming
 Book price: 34.0
 Book author: "The Beauty of Programming" group
 Book language :null
---------------------------------
 Book id : 2
 Book name: ordinary world
 Book price: 56.0
 Book author: Lu Yao
 Book language : Chinese
---------------------------------

JDOM parsing:

--------- Start to analyze the first book -----------------
 Attribute name: id----Attribute value: 1
 Subnode name: name----child node attribute value: the beauty of programming
 Subnode name: price----child node attribute value: 34.0
 Subnode name: author----child node attribute value: "Programming Beauty" group
 --------- End of the analysis of the first book -----------------
 --------- Start to analyze the second book -----------------
 Attribute name: id----Attribute value: 2
 Subnode name: name----child node attribute value: ordinary world
 Child node name: price----child node attribute value: 56.0
 Subnode name: author----child node attribute value: Lu Yao
 Subnode name: language----child node attribute value: Chinese
 --------- End of the analysis of the second book -----------------
 Book id :1
 Book name: the beauty of programming
 Book price: 34.0
 Book author: "The Beauty of Programming" group
 Book language :null
---------------------------------
 Book id : 2
 Book name: ordinary world
 Book price: 56.0
 Book author: Lu Yao
 Book language : Chinese
---------------------------------

DOM4J parsing:

package com.ikok.parsexml;

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

import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

public class dom4jXml {
	
	private static List<Book> bookList = new ArrayList<Book>();
	 // The serial number of the book
	static int bookIndex = 0;
	
	public static void main(String[] args) {
		 // Create an SAXReader object
		SAXReader reader = new SAXReader();
	
		try {
			 / / Load the xml file through the reader's read () method, get the document object
			Document document = reader.read(new File("books.xml"));
			 / / Get the root node
			Element rootElement = document.getRootElement();
			 // Get the iterator
			Iterator iterator = rootElement.elementIterator();
			 // Traverse the iterator to get the information in the root node
			while (iterator.hasNext()) {
				bookIndex++;
				Book bookItem = new Book();
				 System.out.println("---------- start traversing the first" + bookIndex + "book ------------");
				Element book = (Element) iterator.next();
				 / / Get the property name and property value
				List<Attribute> attrList = book.attributes();
				for (Attribute attr : attrList) {
					if(attr.getName().equals("id")){
						bookItem.setId(attr.getValue());
					}
					 System.out.println("property name:" + attr.getName() + "----property value: " + attr.getValue());
				}
				Iterator it = book.elementIterator();
				while (it.hasNext()) {
					Element element = (Element) it.next();
					if(element.getName().equals("name")){
						bookItem.setName(element.getStringValue());
					} else if(element.getName().equals("price")){
						bookItem.setPrice(element.getStringValue());
					} else if(element.getName().equals("author")){
						bookItem.setAuthor(element.getStringValue());
					} else if(element.getName().equals("language")){
						bookItem.setLanguage(element.getStringValue());
					}
					 System.out.println("Subnode Name:" + element.getName() + "----Subnode Property Value:" + element.getStringValue());
				}
				 System.out.println("----------End traversal" + bookIndex + "Book ------------");
				bookList.add(bookItem);
				bookItem = null;
			}
			for (Book item : bookList) {
				 System.out.println("book id :" + item.getId());
				 System.out.println("book name:" + item.getName());
				 System.out.println("book price:" + item.getPrice());
				 System.out.println("book author :" + item.getAuthor());
				 System.out.println("book language :" + item.getLanguage());
				System.out.println("---------------------------------");
			}
		} catch (DocumentException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

Results:

---------- Start traversing the first book ------------
 Attribute name: id----Attribute value: 1
 Subnode name: name----child node attribute value: the beauty of programming
 Subnode name: price----child node attribute value: 34.0
 Subnode name: author----child node attribute value: "Programming Beauty" group
 ---------- End traversing the first book ------------
 ---------- Start traversing the second book ------------
 Attribute name: id----Attribute value: 2
 Subnode name: name----child node attribute value: ordinary world
 Child node name: price----child node attribute value: 56.0
 Subnode name: author----child node attribute value: Lu Yao
 Subnode name: language----child node attribute value: Chinese
 ---------- End traversing the second book ------------
 Book id :1
 Book name: the beauty of programming
 Book price: 34.0
 Book author: "The Beauty of Programming" group
 Book language :null
---------------------------------
 Book id : 2
 Book name: ordinary world
 Book price: 56.0
 Book author: Lu Yao
 Book language : Chinese
---------------------------------

Here, JDOM I use the 2.0.5 package, DOM4J I use the 1.6.1 package.

With the current XML as the target of analysis, the analysis takes time, the SAX takes less time than the DOM, and the DOM4J takes less time than the JDOM.

Currently, the DOM4J parsing XML is also used in the hibernate framework.