java xml文件输出

您可以使用Java中的DOM或SAX库来输出XML文件。以下是使用DOM库的示例代码：

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class XMLWriter {
  public static void main(String[] args) {
    try {
      // 创建DocumentBuilderFactory和DocumentBuilder对象
      DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
      DocumentBuilder docBuilder = docFactory.newDocumentBuilder();

      // 创建一个新的XML文档
      Document doc = docBuilder.newDocument();

      // 创建根节点
      Element rootElement = doc.createElement("employees");
      doc.appendChild(rootElement);

      // 创建子节点
      Element employee = doc.createElement("employee");
      rootElement.appendChild(employee);

      // 添加属性
      employee.setAttribute("id", "1");

      // 添加子节点
      Element firstName = doc.createElement("firstName");
      firstName.appendChild(doc.createTextNode("John"));
      employee.appendChild(firstName);

      Element lastName = doc.createElement("lastName");
      lastName.appendChild(doc.createTextNode("Doe"));
      employee.appendChild(lastName);

      Element age = doc.createElement("age");
      age.appendChild(doc.createTextNode("28"));
      employee.appendChild(age);

      // 将文档写入XML文件
      TransformerFactory transformerFactory = TransformerFactory.newInstance();
      Transformer transformer = transformerFactory.newTransformer();
      DOMSource source = new DOMSource(doc);
      StreamResult result = new StreamResult(new File("employees.xml"));

      transformer.transform(source, result);

      System.out.println("XML文件已创建");

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

在上面的代码中，我们创建了一个名为“employees.xml”的新XML文件，并将其写入“employees”根元素及其子元素和属性。