如何利用JDOM,把JTree中所有节点写入到一个XML文件中？最好有现成的例子。谢谢了。

[worldheart]

rt.........

能给出链接地址最好，或者具体的例子。

本人急用。。。。。

谢谢。。。。。。

[masterz]

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.tree.*;
import java.beans.*;
import java.io.*;
import javax.swing.event.*;
import java.beans.ExceptionListener;

public class DynamicTreeDemo extends JPanel implements ExceptionListener {
private int newNodeSuffix = 1;
String xmlFname = "test.xml";

public DynamicTreeDemo(JFrame frame) {
//create the components
final DynamicTree treePanel = new DynamicTree();
populateTree(treePanel);

JButton addButton = new JButton("Add");
addButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
treePanel.addObject("New Node " + newNodeSuffix++);
}
});

JButton removeButton = new JButton("Remove");
removeButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
treePanel.removeCurrentNode();
}
});

JButton clearButton = new JButton("Clear");
clearButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
treePanel.clear();
}
});
JButton saveButton = new JButton("Save");
saveButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try
{
XMLEncoder xe = new XMLEncoder(new BufferedOutputStream(
new FileOutputStream( xmlFname ) ) );
xe.setExceptionListener(DynamicTreeDemo.this);
xe.writeObject( treePanel.rootNode );
xe.flush();
xe.close();
}
catch(Exception ex)
{ex.printStackTrace();}
}
});
JButton loadButton = new JButton("load");
loadButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try
{
treePanel.clear();
XMLDecoder xe = new XMLDecoder(new FileInputStream(xmlFname));
xe.setExceptionListener(DynamicTreeDemo.this);
treePanel.rootNode = (DefaultMutableTreeNode)xe.readObject();
xe.close();
treePanel.reload();
}
catch(Exception ex)
{ex.printStackTrace();}
}
});
setLayout(new BorderLayout());
treePanel.setPreferredSize(new Dimension(300, 150));
add(treePanel, BorderLayout.CENTER);
JPanel panel = new JPanel();
panel.setLayout(new GridLayout(0,1));
panel.add(addButton);
panel.add(removeButton);
panel.add(clearButton);
panel.add(saveButton);
panel.add(loadButton);
add(panel, BorderLayout.EAST);
}

public void populateTree(DynamicTree treePanel) {
String p1Name = new String("Parent 1");
String p2Name = new String("Parent 2");
String c1Name = new String("Child 1");
String c2Name = new String("Child 2");

DefaultMutableTreeNode p1, p2;

p1 = treePanel.addObject(null, p1Name);
p2 = treePanel.addObject(null, p2Name);

treePanel.addObject(p1, c1Name);
treePanel.addObject(p1, c2Name);

treePanel.addObject(p2, c1Name);
treePanel.addObject(p2, c2Name);
}

public static void main(String[] args) {
JFrame frame = new JFrame("Save tree to xml and load from that xml file:masterz contributes the save/load part");
Container contentPane = frame.getContentPane();
contentPane.setLayout(new GridLayout(1,1));
contentPane.add(new DynamicTreeDemo(frame));
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});

frame.pack();
frame.setVisible(true);
}

public void exceptionThrown(Exception e) {
e.printStackTrace();
}
}

[masterz]

class DynamicTree extends JPanel {
public DefaultMutableTreeNode rootNode;
public DefaultTreeModel treeModel;
protected JTree tree;
private Toolkit toolkit = Toolkit.getDefaultToolkit();

public DynamicTree() {
rootNode = new DefaultMutableTreeNode("Root Node");
treeModel = new DefaultTreeModel(rootNode);
treeModel.addTreeModelListener(new MyTreeModelListener());

tree = new JTree(treeModel);
tree.setEditable(true);
tree.getSelectionModel().setSelectionMode
(TreeSelectionModel.SINGLE_TREE_SELECTION);
tree.setShowsRootHandles(true);

JScrollPane scrollPane = new JScrollPane(tree);
setLayout(new GridLayout(1,0));
add(scrollPane);
}

/** Remove all nodes except the root node. */
public void clear() {
rootNode.removeAllChildren();
treeModel.reload();
}
public void reload()
{
treeModel = new DefaultTreeModel(rootNode);
treeModel.addTreeModelListener(new MyTreeModelListener());

tree = new JTree(treeModel);
tree.setEditable(true);
tree.getSelectionModel().setSelectionMode
(TreeSelectionModel.SINGLE_TREE_SELECTION);
tree.setShowsRootHandles(true);
this.removeAll();
JScrollPane scrollPane = new JScrollPane(tree);
setLayout(new GridLayout(1,0));
add(scrollPane);
invalidate();
repaint();
validate();

}
/** Remove the currently selected node. */
public void removeCurrentNode() {
TreePath currentSelection = tree.getSelectionPath();
if (currentSelection != null) {
DefaultMutableTreeNode currentNode = (DefaultMutableTreeNode)
(currentSelection.getLastPathComponent());
MutableTreeNode parent = (MutableTreeNode)(currentNode.getParent());
if (parent != null) {
treeModel.removeNodeFromParent(currentNode);
return;
}
}

// Either there was no selection, or the root was selected.
toolkit.beep();
}

/** Add child to the currently selected node. */
public DefaultMutableTreeNode addObject(Object child) {
DefaultMutableTreeNode parentNode = null;
TreePath parentPath = tree.getSelectionPath();

if (parentPath == null) {
parentNode = rootNode;
} else {
parentNode = (DefaultMutableTreeNode)
(parentPath.getLastPathComponent());
}

return addObject(parentNode, child, true);
}

public DefaultMutableTreeNode addObject(DefaultMutableTreeNode parent,
Object child) {
return addObject(parent, child, false);
}

public DefaultMutableTreeNode addObject(DefaultMutableTreeNode parent,
Object child,
boolean shouldBeVisible) {
DefaultMutableTreeNode childNode =
new DefaultMutableTreeNode(child);

if (parent == null) {
parent = rootNode;
}

treeModel.insertNodeInto(childNode, parent,
parent.getChildCount());

// Make sure the user can see the lovely new node.
if (shouldBeVisible) {
tree.scrollPathToVisible(new TreePath(childNode.getPath()));
}
return childNode;
}

class MyTreeModelListener implements TreeModelListener {
public void treeNodesChanged(TreeModelEvent e) {
DefaultMutableTreeNode node;
node = (DefaultMutableTreeNode)
(e.getTreePath().getLastPathComponent());

/*
* If the event lists children, then the changed
* node is the child of the node we've already
* gotten. Otherwise, the changed node and the
* specified node are the same.
*/
try {
int index = e.getChildIndices()[0];
node = (DefaultMutableTreeNode)
(node.getChildAt(index));
} catch (NullPointerException exc) {}

System.out.println("The user has finished editing the node.");
System.out.println("New value: " + node.getUserObject());
}
public void treeNodesInserted(TreeModelEvent e) {
}
public void treeNodesRemoved(TreeModelEvent e) {
}
public void treeStructureChanged(TreeModelEvent e) {
}
}
}