java如何解析XML
DOM方式解析XML
Dom解析是将xml文件全部载入到内存，组装成一颗dom树，然后通过节点以及节点之间的关系来解析xml文件,与平台无关,java提供的一种基础的解析XML文件的API,理解较简单，但是由于整个文档都需要载入内存,不适用于文档较大时。 （推荐学习：java课程）
SAX方式解析XML
基于事件驱动,逐条解析,适用于只处理xml数据，不易编码,而且很难同时访问同一个文档中的多处不同数据
JDOM方式解析XML
简化与XML的交互并且比使用DOM实现更快,仅使用具体类而不使用接口因此简化了API,并且易于使用
DOM4j方式解析XML
JDOM的一种智能分支,功能较强大，建议熟练使用
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>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();
}
}
}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);
}
}
}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======");
}
}
}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());
}
}
}
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