解析XML文件之Dom4J

XML资源:

Maven Repository-Dom4J:https://mvnrepository.com/artifact/dom4j/dom4j

Maven Repository-Jaxen:https://mvnrepository.com/artifact/jaxen/jaxen

XML实战:

目标文件(resources/car.xml)


<车辆清单>
    <汽车>
        <车牌 生产时间="2019">奥迪
        <产地>北京
    
    <汽车>
        <车牌 生产时间="2020">奔驰
        <产地>上海
    

读取(Dom4jParseTest.java):

package com.example.test;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.junit.Test;

import java.io.*;
import java.util.List;

public class Dom4jParseTest {
    private File file = new File(this.getClass().getClassLoader().getResource("car.xml").getPath());

    @Test
    public void dom4jRetrieve(){
        try {
            SAXReader saxReader = new SAXReader();
            Document document = saxReader.read(file);
            //显示根元素的名称
            Element rootElement = document.getRootElement();
            System.out.println(rootElement.getName());
            //取得根元素下的所有子元素
            List elements = rootElement.elements();
            System.out.println("根元素下子元素数量:" + elements.size());
            for (Element element:elements){
                //取得子元素的文本
                System.out.println("车牌:" + element.elementText("车牌"));
                System.out.println("产地:" + element.elementText("产地"));
                //取得子元素的属性
                System.out.println("生产时间:" + element.element("车牌").attribute("生产时间").getValue());
            }
        } catch (DocumentException e) {
            e.printStackTrace();
        }
    }
}

增加-默认(Dom4jParseTest.java):

package com.example.test;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.junit.Test;

import java.io.*;

public class Dom4jParseTest {
    private File file = new File(this.getClass().getClassLoader().getResource("car.xml").getPath());

    @Test
    public void dom4jAdd(){
        try {
            SAXReader saxReader = new SAXReader();
            Document document = saxReader.read(file);
            //取得根元素的第一个子元素
            Element firstElement = (Element)document.getRootElement().elements().get(0);
            //添加子元素“单价”并设置文本“30”
            firstElement.addElement("单价").setText("30");
            //写入XML文件
            OutputStream outputStream = new FileOutputStream(file);
            OutputFormat outputFormat = OutputFormat.createPrettyPrint();
            XMLWriter xmlWriter = new XMLWriter(outputStream, outputFormat);
            xmlWriter.write(document);
            xmlWriter.close();
        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

结果文件(car.xml)



<车辆清单> 
  <汽车> 
    <车牌 生产时间="2019">奥迪  
    <产地>北京  
    <单价>30
    
  <汽车> 
    <车牌 生产时间="2020">奔驰  
    <产地>上海 
   

增加-指定位置(Dom4jParseTest.java):

package com.example.test;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.junit.Test;

import java.io.*;
import java.util.List;

public class Dom4jParseTest {
    private File file = new File(this.getClass().getClassLoader().getResource("car.xml").getPath());

    @Test
    public void dom4jAdd(){
        try {
            SAXReader saxReader = new SAXReader();
            Document document = saxReader.read(file);
            //取得根元素下的所有子元素
            List elements = document.getRootElement().elements();
            //创建新元素
            Element element = DocumentHelper.createElement("汽车");
            element.setText("指定位置增加元素");
            //指定位置增加元素
            elements.add(1, element);
            //写入XML文件
            OutputStream outputStream = new FileOutputStream(file);
            OutputFormat outputFormat = OutputFormat.createPrettyPrint();
            XMLWriter xmlWriter = new XMLWriter(outputStream, outputFormat);
            xmlWriter.write(document);
            xmlWriter.close();
        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

结果文件(car.xml)



<车辆清单> 
  <汽车> 
    <车牌 生产时间="2019">奥迪  
    <产地>北京 
    
  <汽车>指定位置增加元素
  <汽车> 
    <车牌 生产时间="2020">奔驰  
    <产地>上海 
   

更新(Dom4jParseTest.java):

package com.example.test;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.junit.Test;

import java.io.*;

public class Dom4jParseTest {
    private File file = new File(this.getClass().getClassLoader().getResource("car.xml").getPath());

    @Test
    public void dom4jUpdate(){
        try {
            SAXReader saxReader = new SAXReader();
            Document document = saxReader.read(file);
            //取得根元素的第一个子元素
            Element firstElement = (Element)document.getRootElement().elements().get(0);
            //修改子元素文本为“深圳”
            firstElement.element("产地").setText("深圳");
            //写入XML文件
            OutputStream outputStream = new FileOutputStream(file);
            OutputFormat outputFormat = OutputFormat.createPrettyPrint();
            XMLWriter xmlWriter = new XMLWriter(outputStream, outputFormat);
            xmlWriter.write(document);
            xmlWriter.close();
        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

结果文件(car.xml)



<车辆清单> 
  <汽车> 
    <车牌 生产时间="2019">奥迪  
    <产地>深圳 
    
  <汽车> 
    <车牌 生产时间="2020">奔驰  
    <产地>上海 
   

删除(Dom4jParseTest.java):

package com.example.test;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.junit.Test;

import java.io.*;

public class Dom4jParseTest {
    private File file = new File(this.getClass().getClassLoader().getResource("car.xml").getPath());

    @Test
    public void dom4jDelete(){
        try {
            SAXReader saxReader = new SAXReader();
            Document document = saxReader.read(file);
            //取得根元素的第一个子元素
            Element firstElement = (Element)document.getRootElement().elements().get(0);
            //删除子元素
            firstElement.remove(firstElement.element("产地"));
            //写入XML文件
            OutputStream outputStream = new FileOutputStream(file);
            OutputFormat outputFormat = OutputFormat.createPrettyPrint();
            XMLWriter xmlWriter = new XMLWriter(outputStream, outputFormat);
            xmlWriter.write(document);
            xmlWriter.close();
        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

结果文件(car.xml)



<车辆清单> 
  <汽车> 
    <车牌 生产时间="2019">奥迪 
    
  <汽车> 
    <车牌 生产时间="2020">奔驰  
    <产地>上海 
   

创建(Dom4jParseTest.java):

package com.example.test;

import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;
import org.junit.Test;

import java.io.*;

public class Dom4jParseTest {
    private File file = new File(this.getClass().getClassLoader().getResource("car.xml").getPath());

    @Test
    public void dom4jCreate(){
        try {
            //创建空的XML
            Document document = DocumentHelper.createDocument();
            //添加根元素
            document.addElement("root").setText("根元素");
            //写入XML文件
            OutputStream outputStream = new FileOutputStream(file);
            OutputFormat outputFormat = OutputFormat.createPrettyPrint();
            XMLWriter xmlWriter = new XMLWriter(outputStream, outputFormat);
            xmlWriter.write(document);
            xmlWriter.close();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

结果文件(car.xml)



根元素

String转换为XML(Dom4jParseTest.java):

package com.example.test;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;
import org.junit.Test;

import java.io.*;

public class Dom4jParseTest {
    private File file = new File(this.getClass().getClassLoader().getResource("car.xml").getPath());

    @Test
    public void dom4jStringToXML(){
        try {
            String text = "<产地>上海";
            //String->XML
            Document document = DocumentHelper.parseText(text);
            //写入XML文件
            OutputStream outputStream = new FileOutputStream(file);
            OutputFormat outputFormat = OutputFormat.createPrettyPrint();
            XMLWriter xmlWriter = new XMLWriter(outputStream, outputFormat);
            xmlWriter.write(document);
            xmlWriter.close();
        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

结果文件(car.xml)



<产地>上海

XML转换为String(Dom4jParseTest.java):

package com.example.test;

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

import java.io.*;

public class Dom4jParseTest {
    private File file = new File(this.getClass().getClassLoader().getResource("car.xml").getPath());

    @Test
    public void dom4jXMLToString(){
        try {
            SAXReader saxReader = new SAXReader();
            Document document = saxReader.read(file);
            //取得根元素
            Element rootElement = document.getRootElement();
            //XML-String
            String xmlStr = rootElement.asXML();
            System.out.println(xmlStr);
        } catch (DocumentException e) {
            e.printStackTrace();
        }
    }
}

XPath定位(Dom4jParseTest.java):

package com.example.test;

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

import java.io.*;
import java.util.List;

public class Dom4jParseTest {
    private File file = new File(this.getClass().getClassLoader().getResource("car.xml").getPath());

    @Test
    public void dom4jXMLToString(){
        try {
            SAXReader saxReader = new SAXReader();
            Document document = saxReader.read(file);
            //取得所有汽车的产地
            String xpath = "//产地";
            List elements = document.selectNodes(xpath);
            for (Element element:elements){
                System.out.println(element.getText());
            }

            //取得第一辆汽车的产地
            Element firstElement = (Element) document.selectSingleNode(xpath);
            System.out.println(firstElement.getText());

            //取得生产时间为2020的车的车牌
            String xpath2020 = "//车牌[@生产时间='2020']";
            Element secondElement = (Element) document.selectSingleNode(xpath2020);
            System.out.println(secondElement.getText());
        } catch (DocumentException e) {
            e.printStackTrace();
        }
    }
}

 

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