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导入dom4j开发包:dom4j-1.6.1.jar
- 在工程下建一个文件夹lib,将dom4j-1.6.1.jar拷到里边。右键add to build path。
- dom4j-1.6.1\lib文件夹下还有一些jar包,是开发过程中dom4j所需要依赖的jar包,如开发过程中报错,则需导入。
用dom4j怎么做呢?
只要是开源jar包提供给你的时候,它会在开源包里面提供相对应的示例程序。入门文档里会清楚的告诉你第一步、第二步、第三步.........
dom4j-1.6.1文件夹里的docs文件夹就是说明文档。双击index.html会到达入门文档的首页。
点击Quick start快速入门。
DOM4j中,获得Document对象的方式有三种:
1. 读取XML文件,获得document对象
SAXReader reader= new SAXReader();
Document document = reader.read(new File("input.xml"));
2. 解析XML形式的文本,得到document对象.
String text ="<members></members>";
Document document = DocumentHelper.parseText(text);
3. 主动创建document对象.
Documentdocument = DocumentHelper.createDocument();
//创建根节点
Element root = document.addElement("members");
dom4j想获取某一节点,只能一级一级往下获取。
package cn.mengmei.dom4j;import java.io.FileOutputStream;
import java.io.IOException;
import java.util.List;import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.junit.Test;public class Demo1 {@Testpublic void read() throws DocumentException{SAXReader reader = new SAXReader();Document document = reader.read("src/book.xml");Element root = document.getRootElement();System.out.println(root.element("书").element("书名").getText());}@Testpublic void readAttr() throws DocumentException{SAXReader reader = new SAXReader();Document document = reader.read("src/book.xml");Element root = document.getRootElement();System.out.println(root.element("书").attributeValue("name"));}@Testpublic void add() throws DocumentException, IOException{SAXReader reader = new SAXReader();Document document = reader.read("src/book.xml");Element root = document.getRootElement();/*Element newNode = DocumentHelper.createElement("售价");newNode.setText("19元");root.element("书").add(newNode);*/root.element("书").addElement("售价").addText("20元");OutputFormat format = OutputFormat.createPrettyPrint();format.setEncoding("UTF-8");XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format);writer.write(document);writer.close();}@Testpublic void update() throws DocumentException, IOException{SAXReader reader = new SAXReader();Document document = reader.read("src/book.xml");Element root = document.getRootElement();//root.element("书").element("售价").setText("50");/*Element ele = (Element)root.element("书").elements("售价").get(2);ele.setText("687");*/root.element("书").setAttributeValue("name", "yyyYYY");OutputFormat format = OutputFormat.createPrettyPrint();format.setEncoding("UTF-8");XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format);writer.write(document);writer.close();}@Testpublic void delete() throws DocumentException, IOException{SAXReader reader = new SAXReader();Document document = reader.read("src/book.xml");Element root = document.getRootElement();Element ele = (Element)root.element("书").elements("售价").get(1);ele.getParent().remove(ele);OutputFormat format = OutputFormat.createPrettyPrint();format.setEncoding("UTF-8");XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format);writer.write(document);writer.close();}//指定位置插元素@Testpublic void add2APoint() throws DocumentException, IOException{SAXReader reader = new SAXReader();Document document = reader.read("src/book.xml");Element root = document.getRootElement();Element newNode = DocumentHelper.createElement("售价");newNode.setText("999");List<Element> list = root.element("书").elements();list.add(1, newNode);OutputFormat format = OutputFormat.createPrettyPrint();format.setEncoding("UTF-8");XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),format);writer.write(document);writer.close();}@Testpublic void findwithXpath() throws DocumentException{SAXReader reader = new SAXReader();Document document = reader.read("src/book.xml");//获取第二个书名的值Element ele = (Element)document.selectNodes("//书名").get(1);System.out.println(ele.getText());}@Testpublic void login() throws DocumentException{SAXReader reader = new SAXReader();Document document = reader.read("src/users.xml");String username = "lisi";String password = "123";Node node = document.selectSingleNode("//user[@username='"+username+"' and @password='"+password+"']");if(node != null){System.out.println("登录成功!");}else{System.out.println("用户名或密码错误......");}}}
<?xml version="1.0" encoding="UTF-8"?><书架> <书 name="yyyYYY"> <书名>Java就业培训教程</书名> <售价>999</售价> <售价>999</售价> <作者>张孝祥</作者> <售价>20元</售价> <售价>20元</售价></书> <书> <书名>JavaScript网页开发</书名> <作者>张孝祥</作者> <售价>28.00元</售价> </书>
</书架>
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