Java的XML创建、解析文档(转载自http://blog.csdn.net/psyuhen/article/details/7539228)

1、使用DOM

优点：可以在内存直接操作节点。

缺点：当文档较大时，消耗内存大。

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/**

*

*/

package com.ee.xml;

import java.io.File;

import java.io.IOException;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

import javax.xml.transform.OutputKeys;

import javax.xml.transform.Transformer;

import javax.xml.transform.TransformerConfigurationException;

import javax.xml.transform.TransformerException;

import javax.xml.transform.TransformerFactory;

import javax.xml.transform.dom.DOMSource;

import javax.xml.transform.stream.StreamResult;

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;

/**

* <pre>

* 使用DOM来创建文档，读取文档等。

* </pre>

* @author ps

*

*/

public class XmlDocument {

private Document document;

/**

* 创建文档

*/

public void createXmlDocument(){

try {

//使用工厂类创建

DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();

DocumentBuilder builder = builderFactory.newDocumentBuilder();

document = builder.newDocument();

} catch (ParserConfigurationException e) {

e.printStackTrace();;

}

}

/**

* <pre>

* 创建XML文档

* 生成的内容如下：

* <?xml version="1.0" encoding="utf-8" standalone="no"?>

* <employees>

* <employee>

* <name>pansen</name>

* <sex>男</sex>

* <age>26</age>

* </employee>

* </employees>

* </pre>

*/

public void createXml(){

Element element = document.createElement("employee");

Element name = document.createElement("name");

Node node = document.createTextNode("pansen");

name.appendChild(node);

element.appendChild(name);

Element sex = document.createElement("sex");

Node sexText = document.createTextNode("男");

sex.appendChild(sexText);

element.appendChild(sex);

Element age = document.createElement("age");

Node ageText = document.createTextNode("26");

age.appendChild(ageText);

element.appendChild(age);

Element root = document.createElement("employees");

root.appendChild(element);

document.appendChild(root);

try {

TransformerFactory transformerFactory = TransformerFactory.newInstance();

Transformer transformer = transformerFactory.newTransformer();

DOMSource domSource = new DOMSource(document);

//设置文档的编码

transformer.setOutputProperty(OutputKeys.ENCODING, "utf-8");

transformer.setOutputProperty(OutputKeys.INDENT, "yes");

File file = new File("d:\\my.xml");//文件名

StreamResult result = new StreamResult(file);

transformer.transform(domSource, result);//生成XML文件

} catch (TransformerConfigurationException e) {

e.printStackTrace();

} catch (TransformerException e) {

e.printStackTrace();

}

}

/**

* 解析XML文档

*/

public void parseXML(){

try {

DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();

DocumentBuilder builder = builderFactory.newDocumentBuilder();

File file = new File("d:\\my.xml");

Document document = builder.parse(file);//把XML文档转换为Document

NodeList employees = document.getChildNodes();

//遍历输出

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

Node employe = employees.item(i);

NodeList nodeList = employe.getChildNodes();

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

Node node = nodeList.item(j);

NodeList employeeMeta = node.getChildNodes();

for (int k = 0; k < employeeMeta.getLength(); k++) {

System.out.println(employeeMeta.item(k).getNodeName()

+ ":" + employeeMeta.item(k).getTextContent());

}

}

}

} catch (ParserConfigurationException e) {

e.printStackTrace();

} catch (SAXException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

}

}

2、使用SAX

优点：不必解析整个文档，消耗内存较小。

缺点：不是持久的；事件过后，若没保存数据，那么数据就丢了；无状态性；从事件中只能得到文本，但不知该文本属于哪个元素。

例子：

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/**

*

*/

package com.ee.xml;

import java.io.File;

import java.io.IOException;

import javax.xml.parsers.ParserConfigurationException;

import javax.xml.parsers.SAXParser;

import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.SAXException;

import com.ee.xml.handle.EmployeeHandler;

/**

* <pre>

* 使用SAX来创建文档，读取文档等。

* </pre>

* @author ps

*

*/

public class SaxXmlDocument extends XmlDocument{

/**

* 解析XML文档

*/

public void parseXML(){

try {

SAXParserFactory parserFactory = SAXParserFactory.newInstance();

SAXParser saxParser = parserFactory.newSAXParser();

File file = new File("d:\\my.xml");

EmployeeHandler handler = new EmployeeHandler();

saxParser.parse(file, handler);

} catch (ParserConfigurationException e) {

e.printStackTrace();

} catch (SAXException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

}

}

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package com.ee.xml.handle;

import java.util.ArrayList;

import java.util.List;

import org.xml.sax.Attributes;

import org.xml.sax.SAXException;

import org.xml.sax.helpers.DefaultHandler;

import com.ee.xml.entity.Employee;

/**

*

* @author ps

*

*/

public class EmployeeHandler extends DefaultHandler{

private Employee employee;

private List<Employee> employeeLists;

private String tagName;

public Employee getEmployee() {

return employee;

}

public void setEmployee(Employee employee) {

this.employee = employee;

}

public List<Employee> getEmployeeLists() {

return employeeLists;

}

public void setEmployeeLists(List<Employee> employeeLists) {

this.employeeLists = employeeLists;

}

@Override

public void startDocument() throws SAXException {

//文档开始，可以做一些初始化的内容

System.err.println("文档开始，可以做一些初始化的内容");

employeeLists = new ArrayList<Employee>();

}

@Override

public void startElement(String uri, String localName, String qName,

Attributes attributes) throws SAXException {

//开始节点调用

System.err.println("开始节点调用");

if("employee".equals(qName)){

employee = new Employee();

//在此可以用来判断获取tagName上的属性值

}

tagName = qName;

System.err.println(qName);

}

@Override

public void endElement(String uri, String localName, String qName)

throws SAXException {

//结束节点调用

System.err.println("结束节点调用");

employeeLists.add(employee);

tagName = null;

}

@Override

public void endDocument() throws SAXException {

//文档结束

System.err.println("文档结束");

}

@Override

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

throws SAXException {

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

System.err.println(val);

if("name".equals(tagName)){

employee.setName(val);

}else if("sex".equals(tagName)){

employee.setSex(val);

}else if("age".equals(tagName)){

employee.setAge(Integer.parseInt(val));

}

}

}

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/**

*

*/

package com.ee.xml.entity;

/**

* @author ps

*

*/

public class Employee {

private String name;

private String sex;

private int age;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getSex() {

return sex;

}

public void setSex(String sex) {

this.sex = sex;

}

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}

}

3、使用DOM4J，需要导入dom4j-1.6.1.jar

DOM4J 是一个非常非常优秀的Java XML API，具有性能优异、功能强大和极端易用使用的特点，同时它也是一个开放源代码的软件。如今你可以看到越来越多的 Java 软件都在使用 DOM4J 来读写 XML，特别值得一提的是连
Sun 的 JAXM 也在用 DOM4J

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/**

*

*/

package com.ee.xml;

import java.io.File;

import java.io.FileOutputStream;

import java.io.FileWriter;

import java.io.IOException;

import java.io.OutputStream;

import java.io.OutputStreamWriter;

import java.io.Writer;

import java.util.Iterator;

import org.dom4j.Document;

import org.dom4j.DocumentException;

import org.dom4j.DocumentHelper;

import org.dom4j.Element;

import org.dom4j.io.SAXReader;

import org.dom4j.io.XMLWriter;

/**

* @author ps

*

*/

public class Dom4jXmlDocument {

public void createXml(){

Document document = DocumentHelper.createDocument();

Element employees = document.addElement("employees");

Element employee = employees.addElement("employee");

Element name = employee.addElement("name");

name.setText("pansen");

Element sex = employee.addElement("sex");

sex.setText("男");

Element age = employee.addElement("age");

age.setText("26");

try {

File file = new File("d:\\dom4j.xml");

OutputStream out = new FileOutputStream(file);

Writer writer = new OutputStreamWriter(out, "utf-8");

//Writer writer = new FileWriter(file);//2 字节的 UTF-8 序列的字节 2 无效。

XMLWriter xmlWriter = new XMLWriter(writer);

xmlWriter.write(document);

xmlWriter.close();

} catch (IOException e) {

e.printStackTrace();

}

}

public void parseXml(){

File file = new File("d:\\dom4j.xml");

SAXReader saxReader = new SAXReader();

try {

Document document = saxReader.read(file);

Element employees = document.getRootElement();

Iterator<Element> iterator = employees.elementIterator();

while(iterator.hasNext()){

Element employee = iterator.next();

Iterator<Element> iter = employee.elementIterator();

while(iter.hasNext()){

Element node = iter.next();

System.err.println(node.getName() + "||" + node.getText());

}

}

} catch (DocumentException e) {

e.printStackTrace();

}

}

}