JTree节点没有按预期添加

Question

我正在尝试解析下面的XML文件并基于它创建一个JTree。

<OBJECTS>
    <WINDOW NAME = "WINDOW 01" URL = "URL 01">
        <PAGE NAME = "PAGE 01" URL = "PAGE URL 01">
        </PAGE>
    </WINDOW>
</OBJECTS>

“窗口01”将添加到根节点“对象列表”，但“页面01”节点不会显示在“窗口01”节点下。下面给出了使用的源代码。请帮忙！！！

public class DataNode extends DefaultMutableTreeNode {    
    private static final long serialVersionUID = 1L;
    public String ObjectType, ObjectName, URL, ElementType;
    public DefaultMutableTreeNode node;

    public DataNode(DefaultMutableTreeNode node, Element element) {
        this.node = node;
        this.ObjectType = element.getTagName();
        this.ObjectName = element.getAttribute("NAME");
        this.URL = element.getAttribute("URL");
        this.ElementType = element.getAttribute("TYPE");
    }

    public DataNode(Element element) {
        this.node = new DefaultMutableTreeNode("OBJECT");
        this.ObjectType = element.getTagName();
        this.ObjectName = "Object List";
        this.URL = "";
        this.ElementType = "";
    }

    @Override
    public String toString() {
        return this.ObjectName;
    }
}

这是主课。编译时不会显示错误或警告。

public class MyOwn {
    private JFrame contentsFrame;

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    MyOwn window = new MyOwn();
                    window.contentsFrame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    public MyOwn() {
        contentsFrame = new JFrame();
        contentsFrame.setTitle("My JTree");
        contentsFrame.setBounds(100, 100, 549, 738);
        contentsFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JTree objectListTree = new JTree(convertXMLtoTree("G:/Collection.xml"));
        objectListTree.setAlignmentY(Component.TOP_ALIGNMENT);
        objectListTree.setAlignmentX(Component.LEFT_ALIGNMENT);

        contentsFrame.getContentPane().add(new JScrollPane(objectListTree));
    }

    private DefaultMutableTreeNode convertXMLtoTree(String Path) {
        NodeList nWindow, nPage;
        DefaultMutableTreeNode dRoot, dWindow, dPage;
        DataNode xRoot, xWindow, xPage;

        try {
            File fXmlFile = new File(Path);
            DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
            Document doc = dBuilder.parse(fXmlFile);

            doc.getDocumentElement().normalize();
            xRoot = new DataNode(doc.getDocumentElement());
            dRoot = new DefaultMutableTreeNode(xRoot);
            nWindow = doc.getDocumentElement().getElementsByTagName("WINDOW");

            for (int i = 0; i < nWindow.getLength(); i++) {
                dWindow = new DefaultMutableTreeNode(((Element)(nWindow.item(i))).getAttribute("NAME"));
                xWindow = new DataNode(dWindow, (Element)(nWindow.item(i)));
                dRoot.add(xWindow);
                nPage = ((Element)(nWindow.item(i))).getElementsByTagName("PAGE");
                for (int j = 0; j < nPage.getLength(); j++) {
                    dPage = new DefaultMutableTreeNode(((Element)(nPage.item(j))).getAttribute("NAME"));
                    xPage = new DataNode(dPage, (Element)(nPage.item(j)));
                    dWindow.add(xPage);
                }
            }
            return dRoot;
        } catch (Exception e) {
            return null;
        }
    }
}

Answer 1

将自定义的DefaultMutableTreeNodeDataNode添加到WINDOW 01的子节点，而不是从未添加到JTree的dWindow。代替

dWindow.add(xPage);

与

xWindow.add(xPage);