Dom4j解析XML

1.Dom4j简介:

   　 DOM4J是 dom4j.org 出品的一个开源 XML 解析包。DOM4J应用于 Java 平台，采用了 Java 集合框架并完全支持 DOM，SAX 和 JAXP。

        DOM4J 使用起来非常简单。只要你了解基本的 XML-DOM 模型，就能使用。

        Dom：把整个文档作为一个对象。

        DOM4J 最大的特色是使用大量的接口。它的主要接口都在org.dom4j里面定义：

　　　　　　　　

　创建xml文件:

<?xml version="1.0" encoding="UTF-8"?>
<phoneInfo>
    <brand name="小米">
        <type name="小米8"/>
        <type name="小米9"/>
        <type name="小米MIX"/>
    </brand>
    <brand name="iPhone">
        <type name="iPhone9"/>
        <type name="iPhoneX"/>
        <type name="iPhoneXS"/>
    </brand>
    <brand name="华为">
        <type name="P20"/>
        <type name="P30"/>
        <type name="P30 pro"/>
    </brand>
</phoneInfo>

 　xml解析——查询

package cn.kgc.dom4jtest;

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

import java.util.Iterator;

/**
 * xml 解析
 */
public class Test {
    public static void main(String[] args) {
        SAXReader saxReader = new SAXReader();
        try {
            //读取xml 文件,并生成document对象,现可通过document来操作文档
            Document document = saxReader.read("src/info.xml");
            //获取到文档的根节点
            Element rootElement = document.getRootElement();
            System.out.println("根节点的名字是"+rootElement.getName());
            //获取子节点列表
            Iterator it = rootElement.elementIterator();
            while (it.hasNext()){
                Element fistChild = (Element) it.next();
                //System.out.println(fistChild.getName());
                //获取节点的属性值
                System.out.println(fistChild.attribute("name").getValue());
                //获取子节点的下一级节点
                Iterator iterator = fistChild.elementIterator();
                while (iterator.hasNext()){
                    Element element = (Element) iterator.next();
                    System.out.println("	"+element.attributeValue("name"));
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

　　xml解析——添加

package cn.kgc.dom4jtest;

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

import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;

/**
 * 添加节点的操作
 */
public class AddTest {
    public static void main(String[] args) {
        SAXReader saxReader = new SAXReader();
        try {
            Document document = saxReader.read("src/info.xml");
            //获取到根节点
            Element rootElement = document.getRootElement();
            //添加一个子节点
            Element brand = rootElement.addElement("brand");
            //给当前节点添加属性
            brand.addAttribute("name","魅族");
            Element type = brand.addElement("type");
            type.addAttribute("name","s16");
            OutputStream os = new FileOutputStream(new File("src/info.xml"));
            XMLWriter xmlWriter = new XMLWriter(os);
            xmlWriter.write(rootElement);
            xmlWriter.flush();
            xmlWriter.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

　　xml解析——修改

package cn.kgc.dom4jtest;

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

import java.io.*;
import java.util.Iterator;

/**
 * 节点修改测试
 */
public class UpdateTest {
    public static void main(String[] args) {
        SAXReader saxReader = new SAXReader();
        try {
            Document document = saxReader.read("src/info.xml");
            //获取根节点
            Element rootElement = document.getRootElement();
            //获取子节点
            Iterator it = rootElement.elementIterator();
            while (it.hasNext()){
                Element element = (Element) it.next();
                System.out.println(element.attributeValue("name"));
                if (element.attributeValue("name").equals("魅族")){
                    Iterator iterator = element.elementIterator();
                    while (iterator.hasNext()){
                        Element type = (Element) iterator.next();
                        if (type.attributeValue("name").equals("s16")){
                            type.addAttribute("name","16 pro");
                        }
                    }
                }
            }
            XMLWriter xmlWriter = new XMLWriter(new FileOutputStream(new File("src/info.xml")));
            xmlWriter.write(document);
            xmlWriter.flush();
            xmlWriter.close();
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

　　xml解析——删除

package cn.kgc.dom4jtest;

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

import java.io.File;
import java.io.FileOutputStream;
import java.util.Iterator;

/**
 * 删除节点
 */

public class DelTest {
    public static void main(String[] args) {
        SAXReader saxReader = new SAXReader();
        try {
            Document document = saxReader.read("src/info.xml");
            Element rootElement = document.getRootElement();
            Iterator iterator = rootElement.elementIterator();
            while (iterator.hasNext()){
                Element brand = (Element) iterator.next();
                if(brand.attributeValue("name").equals("魅族")){
                    //通过父节点来删除子节点
                    brand.getParent().remove(brand);
                }
            }
            XMLWriter xmlWriter = new XMLWriter(new FileOutputStream(new File("src/info.xml")));
            xmlWriter.write(document);
            xmlWriter.flush();
            xmlWriter.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}