java swing的拖放例子

我从java.sun.com和javaworld.com上的例子改过来的一棵文件系统树,支持拖放,CTRL+V复制文件

import java.awt.AlphaComposite;
import java.awt.Component;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.Toolkit;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.dnd.DnDConstants;
import java.awt.dnd.DragGestureEvent;
import java.awt.dnd.DragGestureListener;
import java.awt.dnd.DragSource;
import java.awt.dnd.DragSourceDragEvent;
import java.awt.dnd.DragSourceDropEvent;
import java.awt.dnd.DragSourceEvent;
import java.awt.dnd.DragSourceListener;
import java.awt.dnd.DropTarget;
import java.awt.dnd.DropTargetDragEvent;
import java.awt.dnd.DropTargetDropEvent;
import java.awt.dnd.DropTargetEvent;
import java.awt.dnd.DropTargetListener;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;

import javax.swing.Icon;
import javax.swing.JLabel;
import javax.swing.JTree;
import javax.swing.Timer;
import javax.swing.event.TreeExpansionEvent;
import javax.swing.event.TreeExpansionListener;
import javax.swing.filechooser.FileSystemView;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreePath;

class DragTree extends JTree implements DragGestureListener,
DragSourceListener, DropTargetListener {
BufferedImage ghostImage;

private Rectangle2D ghostRect = new Rectangle2D.Float();

private Point ptOffset = new Point();

private Point lastPoint = new Point();

private TreePath lastPath;

private Timer hoverTimer;

FileNode sourceNode;

public DragTree() {
DragSource dragSource = DragSource.getDefaultDragSource();

dragSource.createDefaultDragGestureRecognizer(this, // component where
// drag originates
DnDConstants.ACTION_COPY_OR_MOVE, // actions
this); // drag gesture recognizer
setModel(createTreeModel());

addTreeExpansionListener(new TreeExpansionListener() {
public void treeCollapsed(TreeExpansionEvent e) {
}

public void treeExpanded(TreeExpansionEvent e) {
TreePath path = e.getPath();

if (path != null) {
FileNode node = (FileNode) path.getLastPathComponent();

if (!node.isExplored()) {
DefaultTreeModel model = (DefaultTreeModel) getModel();
node.explore();
model.nodeStructureChanged(node);
}
}
}
});
this.setCellRenderer(new DefaultTreeCellRenderer() {

public Component getTreeCellRendererComponent(JTree tree,
Object value, boolean selected, boolean expanded,
boolean leaf, int row, boolean hasFocus) {
TreePath tp = tree.getPathForRow(row);
if (tp != null) {
FileNode node = (FileNode) tp.getLastPathComponent();
File f = node.getFile();
try {
Icon icon = FileSystemView.getFileSystemView()
.getSystemIcon(f);
this.setIcon(icon);
this.setLeafIcon(icon);
this.setOpenIcon(icon);
this.setClosedIcon(icon);
this.setDisabledIcon(icon);
} catch (Exception e) {
e.printStackTrace();
}
}
return super.getTreeCellRendererComponent(tree, value,
selected, expanded, leaf, row, hasFocus);
}

});

super.setScrollsOnExpand(true);
new DropTarget(this, DnDConstants.ACTION_COPY_OR_MOVE, this);

// Set up a hover timer, so that a node will be automatically expanded
// or collapsed
// if the user lingers on it for more than a short time
hoverTimer = new Timer(1000, new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (lastPath == null) {
return;
}
if (getRowForPath(lastPath) == 0)
return; // Do nothing if we are hovering over the root node
if (isExpanded(lastPath))
collapsePath(lastPath);
else
expandPath(lastPath);
}
});
hoverTimer.setRepeats(false); // Set timer to one-shot mode

this.addKeyListener(new KeyAdapter() {

public void keyPressed(KeyEvent e) {
int code = e.getKeyCode();