XML的解析（读和写）

我不是女神ヾ 2022-04-03 04:52 227阅读 0赞

1）使用dom4j需要导入dom4j对应的jar包：dom4j-1.6.1.jar  
2）创建SAXReader类的对象来实现读取XML文档，代码如下：  
SAXReader reader = new SAXReader();  
3）使用SAXReader类的read方法获取Document对象，Document 对象是一棵XML文档树的对象，可为我们提供对文档数据的最初（或最顶层）的访问入口，代码如下：  
Document doc = reader.read(new File(“Student.xml”));  
4）使用Document对象的getRootElement方法获取要解析的XML文档的根元素，该方法返回值类型为Element。Element 对象表示 XML文档中的元素。元素可包含属性、其它元素或文本。如果元素含有文本，则在文本节点中表示该文本，代码如下：  
Element root = doc.getRootElement();  
5）接下来，可以使用Element对象提供的方法继续解析XML文档，例如：其elements方法用来获取当前元素下的所有子元素，代码如下：  
List elements = root.elements();

package com.lyc.xml;

import java.util.ArrayList;  
import java.util.List;

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

//xml文件的内容读取  
public class ReadXmlDemo \{

public static void main(String[] args) {
    	SAXReader reader = new SAXReader();
    	try {
    		ArrayList<Student> arrayList = new ArrayList<Student>();
    		Document document = reader.read("student.xml");//文档对象
    		Element root = document.getRootElement();//根元素
    		List<Student> elements = root.elements();//获取跟元素下所有的子元素
    		for (int i = 0; i < elements.size(); i++) {
    			Student stu = new Student();
    			Element ele = (Element) elements.get(i);//获取跟元素所有student对象
    			Attribute attribute = ele.attribute(0);
    			stu.setId(Integer.valueOf(attribute.getValue()));//xml中的属性id attribute.getValue()
    			stu.setName(ele.elementText("name"));//elementText获取元素
    			stu.setAge(Integer.valueOf(ele.elementText("age")));
    			stu.setSex(ele.elementText("gender"));
    			stu.setScore(Double.parseDouble(ele.elementText("score")));
    			arrayList.add(stu);
    		}
    		
    		for (Student student : arrayList) {
    			System.out.println(student);
    		}
    	} catch (DocumentException e) {
    		e.printStackTrace();
    	}
    }

package com.lyc.xml;

import java.io.FileNotFoundException;  
import java.io.FileOutputStream;  
import java.io.IOException;  
import java.io.OutputStreamWriter;  
import java.io.UnsupportedEncodingException;  
import java.util.ArrayList;  
import java.util.List;

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

//xml文件的生成（写）  
public class StringOutputXml \{

public static void main(String[] args) {
    	List<Student> list = new ArrayList<Student>();
    	list.add(new Student(1,"张飞","男",32,89));
    	list.add(new Student(2,"张飞1","男",31,87));
    	list.add(new Student(3,"张飞2","男",33,85));
    	list.add(new Student(4,"张飞3","男",34,84));
    	list.add(new Student(5,"张飞4","男",35,83));
    	
    	Document listdoc = DocumentHelper.createDocument();//创建document对象
    	Element rootElement =  listdoc.addElement("students");//添加根元素
    	
    	for (Student student : list) {//添加子元素和文本内容
    		Element stElement = rootElement.addElement("student");
    		stElement.addAttribute("id",student.getId()+"");
    		stElement.addElement("name").addText(student.getName());
    		stElement.addElement("age").addText(student.getAge()+"");
    		stElement.addElement("gender").addText(student.getSex());
    		stElement.addElement("score").addText(student.getScore()+"");
    	}
    	
    	
    	try {
    		OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("student1.xml"),"utf-8");
    		//创建一个漂亮的输出格式对象
    		OutputFormat opf = OutputFormat.createPrettyPrint();
    		
    		//创建写xml文档对象
    		XMLWriter writer = new XMLWriter(osw,opf);
    		writer.write(listdoc);//将上面创建的文档对象通过XMLWriter写出，写出到student2.xml中
    		osw.close();
    		writer.close();
    		System.out.println("完成");
    	} catch (UnsupportedEncodingException e) {
    		e.printStackTrace();
    	} catch (FileNotFoundException e) {
    		e.printStackTrace();
    	} catch (IOException e) {
    		e.printStackTrace();
    	}
    	
    }

package com.lyc.xml;

/\*\*

*  model
 *  学生类
 *  @author JLB
 *

\*/  
public class Student \{

private int id;
    private String name;
    private String sex;
    private int age;
    private double score;
    public int getId() {
    	return id;
    }
    public void setId(int id) {
    	this.id = id;
    }
    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;
    }
    public double getScore() {
    	return score;
    }
    public void setScore(double score) {
    	this.score = score;
    }
    @Override
    public String toString() {
    	return "Student [id=" + id + ", name=" + name + ", sex=" + sex + ", age=" + age + ", score=" + score + "]";
    }
    public Student() {
    	super();
    }
    public Student(int id, String name, String sex, int age, double score) {
    	super();
    	this.id = id;
    	this.name = name;
    	this.sex = sex;
    	this.age = age;
    	this.score = score;
    }

//操作的xml文件

<?xml version="1.0" encoding="UTF-8"?>