<dependency>
    <groupId>org.dom4j</groupId>
    <artifactId>dom4j</artifactId>
    <version>2.1.1</version>
</dependency>

public class Test {

    public static void main(String[] args) {
        // 获取Document对象
        Document doc = DocumentHelper.createDocument();
        // 添加根元素
        Element root = doc.addElement("persons");
        // 在根元素下添加子节点book
        Element person = root.addElement("person");
        // 给book节点添加id属性
        person.addAttribute("id", "007");
        // 在book下添加子节点并赋值
        person.addElement("name").addText("张三");
        person.addElement("sex").addText("男");
        person.addElement("age").addText("18");

        // 输出到文件中
        OutputFormat outputFormat = OutputFormat.createPrettyPrint();
        XMLWriter writer = null;
        try {
            FileWriter fileWriter = new FileWriter("D:/_temp/person.xml");
            writer = new XMLWriter(fileWriter, outputFormat);
            writer.write(doc);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (writer != null) {
                try {
                    writer.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

    }

}

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

<persons>
  <person id="007">
    <name>张三</name>
    <sex>男</sex>
    <age>18</age>
  </person>
</persons>