Dom4j对XML文档的增删改查操作

本文章使用简单的xml作为事例，展现了使用Dom4j来对xml文件进行操作的一系列代码以及相关问题,在使用Dom4j之前，我们需要下载Dom4j的压缩包，并使用到项目中去，这里不做说明，其中xml代码较为简单，如下：

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

<person> 
<p1 id1 ="aaaa"> 
<name>zhangsan</name>  
<age>4000</age>  
<sex>nv</sex> 
</p1>  
<p1> 
<name>lisi</name>  
<age>20</age> 
</p1> 
</person>

对于xml的相关操作代码如下：

package cn.itcast.dom4j;

import java.io.FileOutputStream;
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.SAXReader;
import org.dom4j.io.XMLWriter;

import cn.itcast.utils.Dom4jUtils;


public class TextDom4j {

/**
 * @param args
 * @throws Exception 
 */
public static void main(String[] args) throws Exception {
// TODO Auto-generated method stub
//selectNameValue(); 
//selectFristNameValue();
//selectSecondNameValue();
//addNode();
//addAgeBefore();
//removeNode();
//deleteNode();
        getNodeValue();
    }

private static void getNodeValue() {
        Document document = Dom4jUtils.getDocument(Dom4jUtils.PATH);

        Element root = document.getRootElement();

        Element p1 = root.element("p1");

        String value = p1.attributeValue("id1");
        System.out.println(value);

    }

private static void deleteNode() {
        Document document = Dom4jUtils.getDocument(Dom4jUtils.PATH);

        Element root = document.getRootElement();

        Element p1 = root.element("p1");

        Element school = p1.element("school");

//school.getParent();
        p1.remove(school);

        Dom4jUtils.rollBack(Dom4jUtils.PATH, document);

    }

private static void removeNode() throws Exception {
        Document document = Dom4jUtils.getDocument(Dom4jUtils.PATH);

        Element root = document.getRootElement();

        Element p1 = root.element("p1");

        Element age = p1.element("age");

        age.setText("4000");

        Dom4jUtils.rollBack(Dom4jUtils.PATH, document);

    }

private static void addAgeBefore() throws Exception {

// SAXReader saxReader = new SAXReader();
// 
// Document document = saxReader.read("src/p.xml");

        Document document = Dom4jUtils.getDocument(Dom4jUtils.PATH);

        Element root = document.getRootElement();

        Element p1  = root.element("p1");

        List<Element> list = p1.elements();

        Element school =DocumentHelper.createElement("school");

        school.setText("xiaoxue");

        list.add(1, school);

        Dom4jUtils.rollBack(Dom4jUtils.PATH, document);

// OutputFormat format = OutputFormat.createPrettyPrint();
// 
// XMLWriter xmlWriter = new XMLWriter(new FileOutputStream("src/p.xml"), format);
// 
// xmlWriter.write(document);
// 
// xmlWriter.close();

    }

private static void addNode() throws Exception {
// TODO Auto-generated method stub
        SAXReader saxReader = new SAXReader();

        Document document = saxReader.read("src/p.xml");

        Element root = document.getRootElement();

        Element p1 = root.element("p1");

        Element sex = p1.addElement("sex");

        sex.setText("nv");

        OutputFormat format = OutputFormat.createPrettyPrint();

        XMLWriter xmlWriter = new  XMLWriter( new FileOutputStream("src/p.xml"),format);

        xmlWriter.write(document);

        xmlWriter.close();
    }

private static void selectSecondNameValue() throws Exception {
// TODO Auto-generated method stub
        SAXReader saxReader = new SAXReader();

        Document document = saxReader.read("src/p.xml");

        Element root =document.getRootElement();

        List<Element> list = root.elements("p1");

        Element p2 = list.get(1);

        Element name2 = p2.element("name");

        String s2 = name2.getText();

        System.out.println(s2);
    }

private static void selectFristNameValue() throws Exception {
// TODO Auto-generated method stub
        SAXReader saxReader = new SAXReader();

        Document document = saxReader.read("src/p.xml");

        Element root = document.getRootElement();

        Element p1 = root.element("p1");

        Element name = p1.element("name");

        String nameValue = name.getText();

        System.out.println(nameValue);

    }

private static void selectNameValue() throws Exception {
// TODO Auto-generated method stub
        SAXReader saxReader = new SAXReader();

        Document document = saxReader.read("src/p.xml");

        Element root = document.getRootElement();

        List<Element> list = root.elements("p1");

for (Element element : list) {

            Element name = element.element("name");

            String nameValue = name.getText();

            System.out.println(nameValue);
        }
    }



}

由于在书写的过程中，存在大量重复的代码，在后期的书写中提取了代码作为另外一个java文件，如下：

package cn.itcast.utils;


import java.io.FileOutputStream;

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

public class Dom4jUtils {

public static final String PATH="src/p.xml";

public static Document getDocument(String path) 
    {
try {
        SAXReader saxReader = new SAXReader();

        Document document = saxReader.read(path);

return document;
        } catch (DocumentException e) {
// TODO Auto-generated catch block
            e.printStackTrace();
        }

return null;

    }
public static void rollBack(String path,Document document) {

try{

        OutputFormat format = OutputFormat.createPrettyPrint();

        XMLWriter xmlWriter = new XMLWriter(new FileOutputStream(path), format);

        xmlWriter.write(document);

        xmlWriter.close();

        }catch(Exception e){
            e.printStackTrace();
        }

    }
}