java读取XML文件的四种方法总结(必看篇)

java读取XML文件的四种方法总结(必看篇)

java操作XML文档主要有四种方式，分别是DOM、SAX、JDOM和DOM4J，DOM和SAX是官方提供的，而JDOM和DOM4J则是引用第三方库的，其中用的最多的是DOM4J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。

下面基于这四种方式来读取XML文件。

第一，以DOM的方式实现。

package xmls;

import org.w3c.dom.Document;

import org.w3c.dom.Element;

import org.w3c.dom.Node;

import org.w3c.dom.NodeList;

import org.xml.sax.SAXException;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

import java.io.File;

import java.io.IOException;

/**

* Created by lenovo on 2017-6-3.

*/

public class DOMReadDemo {

public static void main(String[] args){

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

try{

DocumentBuilder db = dbf.newDocumentBuilder();

Document document = db.parse("src/xmls/DOM.xml");

NodeList booklist = document.getElementsByTagName("book");

for(int i = 0; i < booklist.getLength(); i++){

System.out.println("--------第" + (i+1) + "本书----------");

Element ele = (Element) booklist.item(i);

NodeList childNodes= ele.getChildNodes();

for(int j = 0; j < childNodes.getLength(); j++){

Node n = childNodes.item(j);

if(n.getNodeName() != "#text"){

System.out.println(n.getNodeName() + ":" + n.getTextContent());

}

}

System.out.println("---------------------------------");

}

}catch (ParserConfigurationException e){

e.printStackTrace();

}catch (IOException e){

e.printStackTrace();

}catch (SAXException e){

e.printStackTrace();

}

}

}

第二，以SAX的方式实现。

package xmls;

import javax.xml.parsers.SAXParser;

import javax.xml.parsers.SAXParserFactory;

/**

* Created by lenovo on 2017-6-1.

*/

public class xmlTest2 {

public static void main(String[] args){

SAXParserFactory spf = SAXParserFactory.newInstance();

try{

SAXParser sp = spf.newSAXParser();

SAXParserHandler handler = new SAXParserHandler();

sp.parse("src\\xmls\\book.xml", handler);

}catch (Exception e){

e.printStackTrace();

}

}

}

package xmls;

import org.xml.sax.Attributes;

import org.xml.sax.SAXException;

import org.xml.sax.helpers.DefaultHandler;

/**

* Created by lenovo on 2017-6-1.

*/

public class SAXParserHandler extends DefaultHandler {

@Override

public void startDocument() throws SAXException {

super.startDocument();

System.out.println("SAX解析开始");

}

@Override

public void endDocument() throws SAXException {

super.endDocument();

System.out.println("SAX解析结束");

}

@Override

public void startElement(String s, String s1, String s2, Attributes attributes) throws SAXException {

super.startElement(s, s1, s2, attributes);

System.out.println(s2);

for(int i = 0; i < attributes.getLength(); i++){

String name = attributes.getQName(i);

String value = attributes.getValue(name);

System.out.println("属性值：" + name + "=" + value);

}

}

@Override

public void endElement(String s, String s1, String s2) throws SAXException {

super.endElement(s, s1, s2);

if(s2.equals("book")){

System.out.println("-----------------------");

}

}

@Override

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

super.characters(ch, start, length);

String value = new String(ch, start, length);

if(value.trim().equals("")){

return;

}

System.out.println(value);

}

}

第三，以JDOM的方式实现。

package xmls;

import org.jdom2.Attribute;

import org.jdom2.Document;

import org.jdom2.Element;

import org.jdom2.JDOMException;

import org.jdom2.input.JDOMParseException;

import org.jdom2.input.SAXBuilder;

import java.io.*;

import java.util.List;

/**

* Created by lenovo on 2017-6-2.

*/

public class JDOMTest {

public static void main(String[] args){

SAXBuilder saxBuilder = new SAXBuilder();

InputStream in;

try{

in = new FileInputStream(new File("src\\xmls\\book.xml"));

Document document = saxBuilder.build(in);

vxZRI Element rootElement = document.getRootElement();

List bookList = rootElement.getChildren();

for(Element book: bookList){

System.out.println("第" + (bookList.indexOf(book)+1) + "本书！");

List attrs = book.getAttributes();

for(Attribute attr: attrs){

System.out.println(attr.getName() + "=" + attr.getValue());

}

for(Element item: book.getChildren()){

System.out.println(item.getName() + ":" + item.getValue());

}

System.out.println("------------------------------------");

}

}catch (FileNotFoundException e){

e.printStackTrace();

}catch (JDOMException e){

e.printStackTrace();

}catch (IOException e){

e.printStackTrace();

}

}

}

第四，以DOM4J的方式实现。

package xmls;

import org.dom4j.*;

import org.dom4j.io.OutputFormat;

import org.dom4j.io.SAXReader;

import org.dom4j.io.XMLWriter;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.util.Iterator;

import java.util.List;

/**

* Created by lenovo on 2017-6-2.

*/

public class DOM4JTest {

public void parseXML(){

SAXReader saxReader = new SAXReader();

try{

Document document = saxReader.read(new File("src\\xmls\\book.xml"));

Element rootElement = document.getRootElement();

Iterator it = rootElement.elementIterator();

while (it.hasNext()){

Element book = (Element)it.next();

List attrs = book.attributes();

for(Attribute attr: attrs){

System.out.println("属性名：" + attr.getName() + "---- 属性值：" + attr.getValue() );

}

Iterator cit = book.elementIterator();

while (cit.hasNext()){

Element child = (Element) cit.next();

System.out.println("子节点：" + child.getName());

}

}

}catch (DocumentException e){

e.printStackTrace();

}

}

public static void main(String[] args){

DOM4JTest dom4JTest = new DOM4JTest();

dom4JTest.parseXML();

}

}

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