java操作XML两种方式jdom和dom4j

java操作XML两种方式jdom和dom4j

java提供的工具包可以操作XML，有dom操作方式和sax方式，这两种方式博主也写了文章，可以看我的博客~，基于DOM解析方式，是把整个XML文档加载到内存，转化成DOM树，然后访问DOM树的任何数据，具体使用DocumentBuilder来获取元素节点，然后获取值，这里介绍两种工具，jdom和dom4j，以便于快速开发XML应用程序

• jdom
  jdom是一种使用XML的独特的java工具包
  需要先下载jdom的jar包
  这里给出使用jdom的两种案例

jdom生成xml
例如生成student.xml

<?xml version="1.0" encoding="UTF-8"?>
<student id="001">
	<name>张三</name>
	<sex>男</sex>
	<age>22</age>
</student>

import java.io.FileOutputStream;

import org.jdom2.Attribute;
import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.output.XMLOutputter;

public class Jdom01 {

	public static void main(String[] args) throws Exception {
		//jdom主要是通过建立节点然后赋值，添加子节点父节点实现
		//但是用jdom生成的xml里内容格式混乱，所以一般使用dom4j
		Element student=new Element("student");
		
		Attribute id=new Attribute("id", "001");
		student.setAttribute(id);
		
		Element name=new Element("name");
		name.setText("张三");
		student.addContent(name);
		
		Element sex=new Element("sex");
		sex.setText("男");
		student.addContent(sex);
		
		Element age=new Element("age");
		age.setText("22");
		student.addContent(age);
		
		Document document=new Document(student);
		XMLOutputter out=new XMLOutputter();
		out.setFormat(out.getFormat().setEncoding("UTF-8"));
		out.output(document, new FileOutputStream("src/student.xml"));
	}
}

jdom遍历xml
students.xml

<?xml version="1.0" encoding="UTF-8"?>
<students>
	<student id="001">
		<name>张三</name>
		<sex>男</sex>
		<age>22</age>
	</student>
	<student id="002">
		<name>李四</name>
		<sex>女</sex>
		<age>21</age>
	</student>
</students>

import java.util.List;

import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.input.SAXBuilder;

public class Jdom02 {

	public static void main(String[] args) throws Exception {
		SAXBuilder builder=new SAXBuilder();	//jdom和dom4j都是用SAX来遍历xml的
		Document document=builder.build("src/students.xml");
		Element students=document.getRootElement();		//获取根节点
		List<Element> studentList=students.getChildren();
		for(int i=0;i<studentList.size();i++) {
			Element student=studentList.get(i);
			String id=student.getAttributeValue("id");
			String name=student.getChildText("name");
			String sex=student.getChildText("sex");
			String age=student.getChildText("age");
			System.out.println(id+" "+name+" "+sex+" "+age);
		}
		//相比于原始的方法，这种遍历更方便
	}
}

• dom4j
  dom4j是一个java的XML API,类似于jdom，用来读写XML文件的，许多框架就是使用dom4j来解析xml文件的，比如Hibernate框架
  需要先下载dom4j的jar包
  同样，也给出两种案例

dom4j生成xml
例如生成student.xml

<?xml version="1.0" encoding="UTF-8"?>
<student id="001">
	<name>张三</name>
	<sex>男</sex>
	<age>22</age>
</student>

import java.io.FileOutputStream;

import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;

public class DOM4J01 {

	public static void main(String[] args) throws Exception {
		//这样生成的xml文件是格式化过的，比jdom要好
		Document document=DocumentHelper.createDocument();
		Element student=document.addElement("student");
		student.addAttribute("id", "001");
		
		Element name=student.addElement("name");
		name.setText("张三");
		Element sex=student.addElement("sex");
		sex.setText("男");
		Element age=student.addElement("age");
		age.setText("22");
		
		OutputFormat format=OutputFormat.createPrettyPrint();
		format.setEncoding("UTF-8");
		XMLWriter writer=new XMLWriter(new FileOutputStream("src/student.xml"),format);
		writer.write(document);
		writer.close();
	}
}

dom4j遍历xml
students.xml

<?xml version="1.0" encoding="UTF-8"?>
<students>
	<student id="001">
		<name>张三</name>
		<sex>男</sex>
		<age>22</age>
	</student>
	<student id="002">
		<name>李四</name>
		<sex>女</sex>
		<age>21</age>
	</student>
</students>

import java.util.Iterator;

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

public class DOM4J02 {

	public static void main(String[] args) throws Exception {
		SAXReader reader=new SAXReader();
		Document document=reader.read("src/students.xml");
		Element students=document.getRootElement();
		Iterator<?> iterator=students.elementIterator();
		while(iterator.hasNext()) {
			Element student=(Element)iterator.next();
			System.out.print("学号："+student.attributeValue("id")+" ");
			System.out.print("姓名："+student.elementText("name")+" ");
			System.out.print("性别："+student.elementText("sex")+" ");
			System.out.println("年龄："+student.elementText("age"));
			System.out.println("=================");
		}
	}
}

Dom4J性能要比jdom好，所以建议使用Dom4J