Xml学习

第一部分，创建xml文件及DTD

<?xml version="1.0" encoding="UTF-8"?>
<!-- 引用外部DTD -->
<!DOCTYPE scores SYSTEM "scores.dtd">

<scores>
	<student id="1">
		<name>王同</name>
		<project>java</project>
		<score>89</score>
	</student>

	<student id="2">
		<name>李佳</name>
		<project>sql</project>
		<score>58</score>
	</student>
	
	<student id="3">
		<name>cookie</name>
		<project>php</project>
		<score>99</score>
	</student>	
</scores>

<?xml version="1.0" encoding="UTF-8"?>
<!-- 声明外部DTD -->
<!ELEMENT scores (student+) >
<!ELEMENT student (name, project, score) >
<!ATTLIST student id CDATA #REQUIRED>
<!ELEMENT name (#PCDATA)>
<!ELEMENT project (#PCDATA)>
<!ELEMENT score (#PCDATA)>

 

第二部分，通过dom4j读取xml配置文件

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

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

public class XmlReader {
	public static void main(String[] args) throws DocumentException {

		// 第一步 创建SAXReader对象 ，用于读取xml文件
		SAXReader reader = new SAXReader();

		// 第二步 读取xml文件，得到Document对象
		Document doc = reader.read(new File("src/com/study/demo07/scores2.xml"));

		// 获取根元素
		Element root = doc.getRootElement();
		System.out.println("根元素获取结果：" + root.getName());

		// 获取所有子元素
		Iterator<Element> iterator = root.elementIterator();
		int count = 0;
		while (iterator.hasNext()) {
			// 取出元素
			Element element = iterator.next();

			count++;
			System.out.println("\t子元素获取：" + element.getName());

			// 获取子元素的属性
			Iterator<Attribute> attIterator = element.attributeIterator();
			while (attIterator.hasNext()) {
				Attribute attribute = attIterator.next();
				System.out.println("\t\t子元素属性：" + attribute.getName() + "=" + attribute.getValue());
			}

			// 获取子元素的元素
			Iterator<Element> eleIterator = element.elementIterator();
			while (eleIterator.hasNext()) {
				Element elementElement = eleIterator.next();
				System.out.println("\t\t子元素的元素：" + elementElement.getName() + "=" + elementElement.getStringValue());
			}

		}
		System.out.println("xml文件中子元素的个数是：" + count);

	}
}

运行结果如下：

 

第三部分，生成xml

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;

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

public class CreateXml {
	public static void main(String[] args) throws IOException {

		// 第一步 通过DocumentHelper生成一个Document对象
		Document document = DocumentHelper.createDocument();

		// 第二步 添加得到根元素
		Element root = document.addElement("movies");

		// 第三步 为根元素添加子元素
		Element movie1 = root.addElement("movie");

		// 第四步 为元素添加属性和子元素
		movie1.addAttribute("id", "MOVIE001")/* .addAttribute("package", "01") */;
		Element name = movie1.addElement("name");
		Element data = movie1.addElement("data");
		Element type = movie1.addElement("type");

		// 第五步 为子元素添加文本信息
		name.addText("Love is life");
		data.addText("2000-1-1");
		type.addText("love");

		// 第六步 将document对象输出到xml文件中
		// Writer writer = new FileWriter(new File("src/com/study/demo07/movies.xml"));
		// document.write(writer);
		// writer.close();
		OutputFormat format = OutputFormat.createPrettyPrint();
		XMLWriter writer = new XMLWriter(new FileWriter(new File("src/com/study/demo07/movies22.xml")), format);
		writer.write(document);
		writer.close();
	}
}

运行结果如下：