XML 文档未在 java 中更新

Question

我确实试图在任何地方找到解决方案，但没有任何效果，所以我会在这里试试运气。 我正在尝试实现一个库程序，需要更改我保存书籍信息的 xml 文件。 但是我在实际更新文件时遇到了麻烦。

例如，这是我的 XML 代码调用 books.xml （请忽略描述，我只是在写东西）：

<?xml version="1.0" encoding="UTF-8" ?>
<books>
    <book id="Wüstenrose">
        <author>Waris Dirie</author>
        <storage>1</storage>
        <description>
            This woman who had female circumcision
            did stuff and how she became a model and how she met her husband
            and did other stuff and her family is kinda not really
            but really described in this book.
        </description>
        <students>
            <student>Hans</student>
            <student>Jürgen</student>
        </students>
    </book>
    <book id="Complete Collection of H.P. Lovecraft">
        <author>H.P. Lovecraft</author>
        <storage>5</storage>
        <description>
            A collection... Go guess idiot!
        </description>
        <students>
            <student>Rüdiger</student>
            <student>Wetzls Pretzls</student>
        </students>
    </book>
</books>

现在这是我的 Java 代码（没有 GUI 的重要片段）。 据我所知，更新方法有效，因为值实际上确实发生了变化。 请注意，这还没有完成。 所有书籍的存储价值增加一。 稍后我只想实现一个要更改的值。

import org.w3c.dom.*;
import org.xml.sax.SAXException;

import javax.swing.*;
import javax.swing.border.LineBorder;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.IOException;

public class ReturnBook implements ActionListener {

private JFrame frame;
private Container mainContainer;
private JLabel title;
private JLabel name;
private JLabel student;
private JTextField studentName;
private JTextField book;
private JButton button;
private JPanel flow;
private JPanel flow2;
private JPanel grid;
private JPanel topPanel;


public ReturnBook(){

    frame = new JFrame();
    mainContainer = frame.getContentPane();
    frame.getRootPane().setBorder(BorderFactory.createMatteBorder(4,4,4,4, Color.GRAY));
    mainContainer.setLayout(new BorderLayout(8,5));
    title = new JLabel("Return Book");
    book = new JTextField();
    name = new JLabel("Book:");
    button = new JButton("Return book");
    flow = new JPanel();
    topPanel = new JPanel();
    grid = new JPanel();
    student = new JLabel("Student:");
    studentName = new JTextField();
    flow2 = new JPanel();


    grid.setLayout(new GridLayout(2,1));
    topPanel.setLayout(new FlowLayout(1));
    topPanel.setBorder(new LineBorder(Color.BLACK, 3));
    topPanel.add(title);
    flow.setLayout(new FlowLayout());
    flow.setBackground(Color.LIGHT_GRAY);
    flow2.setLayout(new FlowLayout());
    flow2.setBackground(Color.LIGHT_GRAY);
    grid.setBorder(new LineBorder(Color.BLACK, 3));
    name.setPreferredSize(new Dimension(50,20));
    book.setPreferredSize(new Dimension(100,20));
    student.setPreferredSize(new Dimension(50,20));
    studentName.setPreferredSize(new Dimension(100,20));
    flow.add(name);
    flow.add(book);
    flow2.add(student);
    flow2.add(studentName);
    grid.add(flow);
    grid.add(flow2);
    JPanel buttonLayout = new JPanel();
    buttonLayout.setLayout(new FlowLayout());
    buttonLayout.add(button);
    button.addActionListener(this::actionPerformed);


    mainContainer.add(topPanel, BorderLayout.NORTH);
    mainContainer.add(grid, BorderLayout.CENTER);
    mainContainer.add(buttonLayout, BorderLayout.SOUTH);

    frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    frame.setTitle("Return Book");
    frame.pack();
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
}

@Override
public void actionPerformed(ActionEvent e) {
    DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
    try {
        DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
        Document doc = docBuilder.parse("books.xml");
        doc.getDocumentElement().normalize();

        updateNode(doc);

        doc.getDocumentElement().normalize();
        TransformerFactory transformerFactory = TransformerFactory.newInstance();
        Transformer transformer = transformerFactory.newTransformer();
        DOMSource source = new DOMSource(doc);

        StreamResult result = new StreamResult(new File("books.xml"));
        transformer.setOutputProperty(OutputKeys.INDENT,"yes");
        transformer.transform(source, result);

    } catch (ParserConfigurationException parserConfigurationException) {
        parserConfigurationException.printStackTrace();
    } catch (SAXException saxException) {
        saxException.printStackTrace();
    } catch (IOException ioException) {
        ioException.printStackTrace();
    } catch (TransformerConfigurationException transformerConfigurationException) {
        transformerConfigurationException.printStackTrace();
    } catch (TransformerException transformerException) {
        transformerException.printStackTrace();
    }

}

private void updateNode(Document doc) {
    NodeList bookNodeList = doc.getElementsByTagName("book");
    Element bk = null;
    for (int i = 0; i < bookNodeList.getLength(); i++) {
        bk = (Element) bookNodeList.item(i);
        Node storage = bk.getElementsByTagName("storage").item(0).getFirstChild();
        String value = Integer.toString(Integer.parseInt(storage.getTextContent()) + 1);
        storage.setNodeValue(value);
        System.out.println(storage.getNodeValue());
    }
}
}

所以。 我尝试访问 xml 文件，获取存储值，将其加一并更新现有的 xml 文件。 该文件虽然没有改变，但我需要访问更新的文件以获取其他方法。 有人可以看到我做错了什么吗？

编辑：我输入了整个 class 只是为了确保我没有错过任何东西。 第一部分只是 Gui 的东西，所以你可以忽略它。 基本上我尝试使用按钮来实现更改。