使用Dom4j读写xml文件

引入依赖

<dependency>
    <groupId>dom4j</groupId>
    <artifactId>dom4j</artifactId>
    <version>1.5.2</version>
</dependency>

xml范本

book.xml文件

<books>
    <book id="001">
        <title>Harry Potter</title>
        <author>J K. Rowling</author>
    </book>
    <book id="002">
        <title>Learning XML</title>
        <author>Erik T. Ray</author>
    </book
</books>

解析xml文件

使用list方式

import java.io.File;
import java.util.List;
import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
public class Demo {
 public static void main(String[] args) throws Exception {
  SAXReader reader = new SAXReader();
  File file = new File("books.xml");
  Document document = reader.read(file);
  Element root = document.getRootElement();
  List<Element> childElements = root.elements();
  for (Element child : childElements) {
   //未知属性名情况下
   /*List<Attribute> attributeList = child.attributes();
   for (Attribute attr : attributeList) {
    System.out.println(attr.getName() + ": " + attr.getValue());
   }*/

   //已知属性名情况下
   System.out.println("id: " + child.attributeValue("id"));

   //未知子元素名情况下
   /*List<Element> elementList = child.elements();
   for (Element ele : elementList) {
    System.out.println(ele.getName() + ": " + ele.getText());
   }
   System.out.println();*/
、
   //已知子元素名的情况下
   System.out.println("title" + child.elementText("title"));
   System.out.println("author" + child.elementText("author"));
  }
 }

}

使用Iterator迭代器的方式来解析xml

import java.io.File;
import java.util.Iterator;
import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
public class Demo {
 public static void main(String[] args) throws Exception {
  SAXReader reader = new SAXReader();
  Document document = reader.read(new File("books.xml"));
  Element root = document.getRootElement();

  Iterator it = root.elementIterator();
  while (it.hasNext()) {
   Element element = (Element) it.next();

   //未知属性名称情况下
   /*Iterator attrIt = element.attributeIterator();
   while (attrIt.hasNext()) {
    Attribute a  = (Attribute) attrIt.next();
    System.out.println(a.getValue());
   }*/

   //已知属性名称情况下
   System.out.println("id: " + element.attributeValue("id"));

   //未知元素名情况下
   /*Iterator eleIt = element.elementIterator();
   while (eleIt.hasNext()) {
    Element e = (Element) eleIt.next();
    System.out.println(e.getName() + ": " + e.getText());
   }
   System.out.println();*/

   //已知元素名情况下
   System.out.println("title: " + element.elementText("title"));
   System.out.println("author: " + element.elementText("author"));
   System.out.println();
  }
 }
}

写入xml文件

public static void main(String[] args) throws IOException {
      Document doc = DocumentHelper.createDocument();
      //增加根节点
      Element books = doc.addElement("books");
      //增加子元素
      Element book1 = books.addElement("book");
      Element title1 = book1.addElement("title");
      Element author1 = book1.addElement("author");

      //为子节点添加属性
      book1.addAttribute("id", "001");
      //为元素添加内容
      title1.setText("西游记");
      author1.setText("吴承恩");

      Element book2 = books.addElement("book");
      Element title2 = book2.addElement("title");
      Element author2 = book2.addElement("author");

      book2.addAttribute("id", "002");
      book2.addAttribute("price","500");
      title2.setText("水浒传");
      author2.setText("施耐庵");

      //实例化输出格式对象
      OutputFormat format = OutputFormat.createPrettyPrint();
      //设置输出编码
      format.setEncoding("UTF-8");
      //创建需要写入的File对象
      File file = new File("D:" + File.separator + "books.xml");
      //生成XMLWriter对象，构造函数中的参数为需要输出的文件流和格式
      XMLWriter writer = new XMLWriter(new FileOutputStream(file), format);
      //开始写入，write方法中包含上面创建的Document对象
      writer.write(doc);
      System.out.println("生成成功");
}

查看效果