Dom4j读写xml

直接呈现代码，代码中有详细注释

Dom4jFirst.java

package com.bao;
import java.io.File;
import java.io.FileOutputStream;
import java.util.ArrayList;
import java.util.Iterator;
import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
/**
 * 程序值得优化的地方：在Student中，根据数据的特点，college也应该是一个对象
 */
public class Dom4jFirst {
	public static void main(String[] args) {
		try {
			writeXml();
		} catch (Exception e) {
			System.out.println("写xml出现异常");
			e.printStackTrace();
		}
		
		
		
		
		ArrayList<Student> students = new ArrayList<Student>();
		try {
			readXML("src/com/bao/studentInfo.xml", students);
		} catch (Exception e) {
			System.out.println("解析xml出现问题");
			e.printStackTrace();
		}
		Iterator<Student> iterator = students.iterator();
		Student student = null;
		while (iterator.hasNext()) {
			student = iterator.next();
			System.out.println(student);
		}
	}
	
	/**
	 * 借助于Dom4j写xml文件是非常轻松的事情，总体思路就是首先构建根元素，然后根元素构建子元素。
	 * 
	 * 当然，子元素也可以构建自己的子元素
	 * @throws Exception
	 */
		public static void writeXml()throws Exception{
			Document document = DocumentHelper.createDocument();
			
			Element root = document.addElement("persons");
			
			Element element_1 = root.addElement("person").addAttribute("age", "24");
			element_1.addElement("name").addText("冯小卫");
			element_1.addElement("性别").addText("男");
			
			Element element_2 = root.addElement("person").addAttribute("age", "22");
			element_2.addElement("name").addText("秦珊珊");
			element_2.addElement("性别").addText("女");
			
			
			XMLWriter writer = new XMLWriter(new FileOutputStream("persons.xml"));
			
			writer.write(document);
			writer.close();
		}
		/**
		 * 
		 *Dom4j解析xml例子
		 * 
		 *解析思路：
		 * 
		 *首先获取根元素root，然后通过root元素获取root子元素的遍历器。
		 * 
		 *得到遍历器以后，移动到第一个子元素上，解析参数。
		 * 
		 *解析参数结束以后，开始解析这个子元素的子元素。
		 * 
		 * 
		 */
	/**
	 * 遍历整个XML文件，获取所有节点的值与其属性的值，并放入ArrayList中
	 * 
	 * @param filename
	 *            String 待遍历的XML文件（相对路径或者绝对路径）
	 */
	@SuppressWarnings("unchecked")
	public static void readXML(String filename, ArrayList<Student> students) throws Exception {
		SAXReader saxReader = new SAXReader();
		Document document = saxReader.read(new File(filename));
		Element root = document.getRootElement();// 获取根元素
		Iterator<Element> iter = root.elementIterator();
		Student student = null;
		Element element = null;
		Attribute ageAttr = null;
		Attribute leaderAttr = null;
		while (iter.hasNext()) {
			student = new Student();
			element = iter.next();
			ageAttr = element.attribute("age");
			if (ageAttr != null) {
				String age = ageAttr.getValue();
				if (age != null && !age.equals("")) {
					student.setAge(age);
				} else {
					student.setAge(20 + "");
				}
			} else {
				student.setAge(20 + "");
			}
			Iterator<Element> iterInner = element.elementIterator();
			while (iterInner.hasNext()) {
				Element elementInner = iterInner.next();
				if (elementInner.getName().equals("college")) {
					student.setCollege(elementInner.getText());
					leaderAttr = elementInner.attribute("leader");
					if (leaderAttr != null) {
						String leader = leaderAttr.getValue();
						if (leader != null && !leader.equals("")) {
							student.setLeader(leader);
						} else {
							student.setLeader("leader");
						}
					} else {
						student.setLeader("leader");
					}
				} else {
					if (elementInner.getName().equals("name")) {
						student.setName(elementInner.getText());
					} else if (elementInner.getName().equals("telephone")) {
						student.setTelephone(elementInner.getText());
					} else if (elementInner.getName().equals("notes")) {
						student.setNotes(elementInner.getText());
					}
				}
			}
			students.add(student);
		}
	}
}

Student.java

package com.bao;
public class Student {
	private String age;
	private String name;
	private String college;
	private String telephone;
	private String notes;
	private String leader;
	public String getAge() {
		return age;
	}
	public void setAge(String age) {
		this.age = age;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getCollege() {
		return college;
	}
	public void setCollege(String college) {
		this.college = college;
	}
	public String getTelephone() {
		return telephone;
	}
	public void setTelephone(String telephone) {
		this.telephone = telephone;
	}
	public String getNotes() {
		return notes;
	}
	public void setNotes(String notes) {
		this.notes = notes;
	}
	public void setLeader(String leader) {
		this.leader = leader;
	}
	public String getLeader() {
		return leader;
	}
	@Override
	public String toString() {
		return "age:" + getAge() + " collage:" + getCollege() + " leader:" + getLeader() + " name:" + getName() + " notes:" + getNotes() + " tel:"
				+ getTelephone();
	}
}

studentInfo.xml

<?xml version="1.0" encoding="gb2312"?>
<students>
	<student age="25"><!--如果没有age属性，默认的为20-->
		<name>崔卫兵</name>
		<college>PC学院</college>
		<telephone>62354666</telephone>
		<notes>男,1982年生,硕士，现就读于北京邮电大学</notes>
	</student>
	<student>
		<name>cwb</name>
		<college leader="学院领导">PC学院</college><!--如果没有leader属性，默认的为leader-->
		<telephone>62358888</telephone>
		<notes>男,1987年生,硕士，现就读于中国农业大学</notes>
	</student>
	<student age="45">
		<name>xxxxx</name>
		<college leader="">xxx学院</college>
		<telephone>66666666</telephone>
		<notes>注视中，注释中</notes>
	</student>
	<student age="">
		<name>lxx</name>
		<college>yyyy学院</college>
		<telephone>88888888</telephone>
		<notes>注视中111，注释中222</notes>
	</student>
</students>