Dom4j操作xml文件

　　xml文件在工程中经常会用到，如web.xml、spring的相关配置、Mybatis的xml文件等等，很多开源框架都有对xml文件的解析。下面用dom4j来写一个小demo，操作xml文件。

1、pom.xml文件

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

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.cust</groupId>
  <artifactId>base</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>base Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>
    <!-- https://mvnrepository.com/artifact/dom4j/dom4j -->
    <dependency>
      <groupId>dom4j</groupId>
      <artifactId>dom4j</artifactId>
      <version>1.6</version>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
  </dependencies>

  <build>
    <finalName>base</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

2、装载数据实体

package com.operaterXml;

/**
 * 需写入/读取的实体类
 */

public class Student {

    private String name;

    private String address;

    public Student(String name, String address) {
        this.name = name;
        this.address = address;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getName() {
        return name;
    }

    public String getAddress() {
        return address;
    }

}

3、写入xml文件

package com.operaterXml;

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.XMLWriter;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.lang.reflect.Field;
import java.text.DateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

/**
 * @ClassName WriterOperaterXml
 * @Description 写入xml
 * @Author snails
 * @Version 1.0
 */
public class WriterOperaterXml {

    public static void main(String[] args) throws DocumentException, IllegalAccessException, IOException {
        // 获取数据信息
        List<Student> stuInfo = getStuInfo();
        File simpleXml = new File("src/simpleXml.xml");
        // 获取document对象
        Document document = getDocument(stuInfo);
        // 写入xml文件
        writeXml(simpleXml, document);
    }

    /**
     * 获取Document对象
     * @param stuList
     * @return
     * @throws DocumentException
     * @throws IllegalAccessException
     * @throws IOException
     */
    public static Document getDocument(List<Student> stuList) throws DocumentException, IllegalAccessException, IOException {
        // 创建document对象
        Document document = DocumentHelper.createDocument();
        // 创建根节点
        Element root = document.addElement("root");
        // 生成子节点
        Element header = root.addElement("header");
//        Element body = root.addElement("body");
        // 生成子节点header内容
        header.addElement("ver").setText("1.0");
        header.addElement("date").setText(DateFormat.getDateInstance().format(new Date()));
        header.addElement("number").setText("1");
        // 生成自子节点body及其子节点info内容
        Element body = root.addElement("body");
        for (Student stu : stuList) {
            Element info = body.addElement("info");
            Field[] declaredFields = stu.getClass().getDeclaredFields();
            for (Field field : declaredFields) {
                field.setAccessible(true);
                Element element = info.addElement(field.getName());
                element.setText(String.valueOf(field.get(stu)));
            }
        }
        return document;
    }

    /**
     * 将数据流写入xml文件
     * @param file
     * @param document
     * @throws IOException
     */
    public static void writeXml(File file, Document document) throws IOException {
        XMLWriter xmlWriter = null;
        FileOutputStream fos = null;
        try{
            fos = new FileOutputStream(file);
            // 生成xml格式
            OutputFormat prettyPrint = OutputFormat.createPrettyPrint();
            xmlWriter = new XMLWriter(fos, prettyPrint);
            // 是否使用转义，默认使用转义
            xmlWriter.setEscapeText(false);
            // 将流写入xml文件
            xmlWriter.write(document);
        } finally {
            if(fos != null){
                fos.close();
            }
            if(xmlWriter != null){
                xmlWriter.close();
            }
        }
    }

    /**获取数据信息
     * @return
     */
    public static List<Student> getStuInfo(){
        ArrayList<Student> students = new ArrayList<>();
        students.add(new Student("张三", "四川"));
        students.add(new Student("李四", "福建"));
        students.add(new Student("王五", "海南"));
        return students;
    }
}

4、生成xml文件

5、解析xml文件

package com.operaterXml;

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

import java.io.File;
import java.util.List;

/**
 * @ClassName ReaderOperaterXml
 * @Description 读取xml
 * @Author snails
 * @Version 1.0
 */
public class ReaderOperaterXml {
    public static void main(String[] args) throws Exception {
        File file = new File("src/simpleXml.xml");
        parseXml(file);
    }

    /**
     * 解析xml文件
     * @param file
     * @throws DocumentException
     */
    public static void parseXml(File file) throws DocumentException {
        // 获取document对象
        Document doc = new SAXReader().read(file);
        // 获取根节点信息
        Element rootElement = doc.getRootElement();
        System.out.println("----------------------header元素节点下的内容----------------------");
        List<Element> headerChildNodes = rootElement.element("header").elements();
        for (int i = 0; i < headerChildNodes.size(); i++) {
            System.out.println("header元素节点下子节点的文本节点名称:" + headerChildNodes.get(i).getName() + ";  子节点的文本节点内容: " + headerChildNodes.get(i).getText());
        }
        System.out.println("----------------------body元素节点下的内容 info----------------------");
        // 获取body节点下的子节点
        List<Element> bodyChildNodes = rootElement.element("body").elements("info");
        for (Element ele: bodyChildNodes) {
            // 获取info节点下的子节点
            List<Element> elements = ele.elements();
            for (int i = 0; i < elements.size(); i++) {
                System.out.println("info元素节点下子节点的文本节点名称:" + elements.get(i).getName() + ";  子节点的文本节点内容: " + elements.get(i).getText());
            }
        }
    }

}