使用Dom4j解析XML文件

      与利用DOM、SAX、JAXP机制来解析xml相比，DOM4J 表现更优秀，具有性能优异、功能强大和极端易用使用的特点，只要懂得DOM基本概念，就可以通过dom4j的api文档来解析xml。dom4j是一套开源的api。实际项目中，往往选择dom4j来作为解析xml的利器。

所用jar包：dom4j-1.6.1.jar

 

常用API

class org.dom4j.io.SAXReader

• read  提供多种读取xml文件的方式，返回一个Domcument对象

interface org.dom4j.Document

• iterator  使用此法获取node
• getRootElement  获取根节点

interface org.dom4j.Node

• getName  获取node名字，例如获取根节点名称为bookstore
• getNodeType  获取node类型常量值，例如获取到bookstore类型为1——Element
• getNodeTypeName  获取node类型名称，例如获取到的bookstore类型名称为Element

interface org.dom4j.Element

• attributes  返回该元素的属性列表
• attributeValue  根据传入的属性名获取属性值
• elementIterator  返回包含子元素的迭代器
• elements  返回包含子元素的列表

interface org.dom4j.Attribute

• getName  获取属性名
• getValue  获取属性值

interface org.dom4j.Text

• getText  获取Text节点值

interface org.dom4j.CDATA

• getText  获取CDATA Section值

interface org.dom4j.Comment

• getText  获取注释 

需要解析的xml文件：people.xml

<people city="BeiJing">
    <student name="Jack" age="10">My name is Jack!</student>
    <student name="Lucy" age="11">My name is Lucy!</student>
    <student name="James" age="12"/>
    <teacher name="Jason" age="25">I am a teacher!</teacher>
    <teacher name="Michael" age="30">I am a teacher too!</teacher>
</people>

首先根据xml文档构建javabean：

package bean;

import java.util.List;

public class People {
    private String city;
    private List<Student> student;
    private List<Teacher> teacher;
    
    public String getCity() {
        return city;
    }
    public void setCity(String city) {
        this.city = city;
    }
    public List<Student> getStudent() {
        return student;
    }
    public void setStudent(List<Student> student) {
        this.student = student;
    }
    public List<Teacher> getTeacher() {
        return teacher;
    }
    public void setTeacher(List<Teacher> teacher) {
        this.teacher = teacher;
    }
}

package bean;

public class Student {
    private String name;
    private int age;
    private String text;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getResult() {
        return text;
    }
    public void setResult(String result) {
        this.text = result;
    }
    public Student(String name, int age, String text) {
        super();
        this.name = name;
        this.age = age;
        this.text = text;
    }
}

package bean;

public class Teacher {
    private String name;
    private int age;
    private String text;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getResult() {
        return text;
    }
    public void setResult(String result) {
        this.text = result;
    }
    public Teacher(String name, int age, String text) {
        super();
        this.name = name;
        this.age = age;
        this.text = text;
    }
}

解析代码如下：

package xml;

import java.io.File;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

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

import bean.People;
import bean.Student;
import bean.Teacher;

public class Dom4jParserXML {
    public static People parseXml(String xmlPath) {
        File xmlFile = new File(xmlPath);
        System.out.println(xmlFile.getPath());
        
        if (xmlFile.exists()) {
            SAXReader reader = new SAXReader();
            People people = new People();
            try {
                // 读入文档流
                Document document = reader.read(xmlFile);
                // 获取根节点
                Element root = document.getRootElement();

                List<Student> students = new ArrayList<Student>();
                List<Teacher> teachers = new ArrayList<Teacher>();
                
                people.setCity(root.attributeValue("city"));
                // 解析student节点
                for (Iterator<Element> iterator = root
                        .elementIterator("student"); iterator.hasNext();) {
                    Element eStudent = iterator.next();
                    String text = eStudent.getText();
                    
                    Student student = new Student(
                            eStudent.attributeValue("name"),
                            Integer.parseInt(eStudent.attributeValue("age")),text);
                    students.add(student);
                }
                // 解析teacher节点
                for (Iterator<Element> iterator = root
                        .elementIterator("teacher"); iterator.hasNext();) {
                    Element eTeacher = iterator.next();
                    String text = eTeacher.getText();
                    
                    Teacher teacher = new Teacher(
                            eTeacher.attributeValue("name"),
                            Integer.parseInt(eTeacher.attributeValue("age")),text);
                    teachers.add(teacher);
                }
                people.setStudent(students);
                people.setTeacher(teachers);
                
                System.out.println("Parse success!");
            } catch (DocumentException e) {
                e.printStackTrace();
            }
            return people;
        } else {
            System.err.println("File is not exist!");
            return null;
        }
    }

    public static void main(String[] args) throws URISyntaxException {
        String xmlPath = "E://xml//people.xml";
        System.out.println("File full path is " + xmlPath);
        // 解析people.xml
        People p = parseXml(xmlPath);

        // 处理解析结果
        System.out.println("The city is : " + p.getCity());
        List<Student> sList = p.getStudent();
        List<Teacher> tList = p.getTeacher();
        for (Student s : sList) {
            System.out.println(s.getName() + "->" + s.getAge() + "->" + s.getResult());
        }
        for (Teacher t : tList) {
            System.out.println(t.getName() + "->" + t.getAge() + "->" + t.getResult());
        }
    }
}

运行结果：

File full path is E://xml//people.xml
E:\xml\people.xml
Parse success!
The city is : BeiJing
Jack->10->My name is Jack!
Lucy->11->My name is Lucy!
James->12->
Jason->25->I am a teacher!
Michael->30->I am a teacher too!