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我有一個JTree，我想將一些文件從JTree導出到資源管理器。要做到這一點，我使用TransferHandler和風味：DataFlavor.javaFileListFlavor。所以，資源管理器可以導入拖動的文件。問題是我的文件在服務器上，當可移植對象放在資源管理器上時我需要下載它們。Drag n Drop：在將文件從組件拖放到資源管理器，查找程序等時的操作
如何在啓動瀏覽器時啓動我的下載方法？我怎樣才能知道我的下載文件的目標文件夾？
這裏的樣本：
import java.awt.BorderLayout;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.swing.BorderFactory;
import javax.swing.DropMode;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.TransferHandler;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreePath;
import javax.swing.tree.TreeSelectionModel;
public class JTreeDnDSample extends JFrame
{
protected JTree _tree;
private DefaultTreeModel treeModel;
private DefaultMutableTreeNode rootNode;
private JScrollPane border;
public static void main(String[] args)
{
new JTreeDnDSample().setVisible(true);
}
public JTreeDnDSample()
{
super("Dnd");
initializeTree();
this.setLayout(new BorderLayout());
border = new JScrollPane(this._tree);
border.setBorder(BorderFactory.createTitledBorder("Tree"));
this.add(border, BorderLayout.CENTER);
this.setSize(400, 800);
}
protected void initializeTree()
{
this.rootNode = new DefaultMutableTreeNode("Root folder");
this.treeModel = new DefaultTreeModel(rootNode);
_tree = new JTree(treeModel);
_tree.setName("TREE");
_tree.setDragEnabled(true);
_tree.setDropMode(DropMode.ON_OR_INSERT);
_tree.setTransferHandler(new TreeTransferHandler());
_tree.setShowsRootHandles(true);
_tree.getSelectionModel().setSelectionMode(TreeSelectionModel.DISCONTIGUOUS_TREE_SELECTION);
_tree.setRowHeight(26);
//tree creation
DefaultMutableTreeNode folder = new DefaultMutableTreeNode("folder1");
DefaultMutableTreeNode file = new DefaultMutableTreeNode("file1.txt");
folder.add(file);
file = new DefaultMutableTreeNode("file2.txt");
folder.add(file);
rootNode.add(folder);
folder = new DefaultMutableTreeNode("folder2");
file = new DefaultMutableTreeNode("file1.txt");
folder.add(file);
file = new DefaultMutableTreeNode("file2.txt");
folder.add(file);
file = new DefaultMutableTreeNode("file3.txt");
folder.add(file);
rootNode.add(folder);
}
public void setTitle(String title)
{
border.setBorder(BorderFactory.createTitledBorder(title));
}
}
class TreeTransferHandler extends TransferHandler
{
private DataFlavor nodesFlavor;
private DataFlavor[] flavors = new DataFlavor[1];
private DefaultMutableTreeNode[] nodesToRemove;
public TreeTransferHandler()
{
super();
try
{
String mimeType = DataFlavor.javaJVMLocalObjectMimeType +
";class=\"" +
DefaultMutableTreeNode[].class.getName() +
"\"";
nodesFlavor = new DataFlavor(mimeType);
flavors[0] = nodesFlavor;
}
catch(ClassNotFoundException e)
{
System.out.println("ClassNotFound: " + e.getMessage());
}
}
public boolean importData(TransferHandler.TransferSupport support)
{
Transferable data = support.getTransferable();
if(!canImport(support))
{
return false;
}
// Extract transfer data.
List<DefaultMutableTreeNode> nodes = new ArrayList<DefaultMutableTreeNode>();
try
{
System.out.println("IMPORT DATA");
nodes = (List<DefaultMutableTreeNode>) data.getTransferData(nodesFlavor);
/*List<File> files = (List<File>)data.getTransferData(DataFlavor.javaFileListFlavor);
System.out.println("File size: " + nodes.size());
for(File f : files)
{
System.out.println("File: "+f.getName());
}*/
}
catch(UnsupportedFlavorException ufe)
{
System.out.println("UnsupportedFlavor: " + ufe.getMessage());
}
catch(java.io.IOException ioe)
{
System.out.println("I/O error: " + ioe.getMessage());
}
catch(Exception e)
{
e.printStackTrace();
}
// Get drop location info inside the tree.
JTree.DropLocation dl =
(JTree.DropLocation)support.getDropLocation();
int childIndex = dl.getChildIndex();
TreePath dest = dl.getPath();
DefaultMutableTreeNode parent = (DefaultMutableTreeNode)dest.getLastPathComponent();
JTree tree = (JTree)support.getComponent();
DefaultTreeModel model = (DefaultTreeModel)tree.getModel();
// Configure for drop mode.
int index = childIndex; // DropMode.INSERT
if(childIndex == -1) // DropMode.ON
index = parent.getChildCount();
// Add data to model.
for(int i = 0; i < nodes.size(); i++)
{
model.insertNodeInto(nodes.get(i), parent, index++);
}
// Remove nodes saved in nodesToRemove in createTransferable.
for(int i = 0; i < nodesToRemove.length; i++)
{
model.removeNodeFromParent(nodesToRemove[i]);
}
return true;
}
public boolean canImport(TransferHandler.TransferSupport support)
{
if(!support.isDrop())
return false;
support.setShowDropLocation(true);
if(!support.isDataFlavorSupported(DataFlavor.javaFileListFlavor)
&& !support.isDataFlavorSupported(nodesFlavor))
return false;
// Do not allow a drop on the drag source selections.
JTree.DropLocation dl = (JTree.DropLocation)support.getDropLocation();
JTree tree = (JTree)support.getComponent();
int dropRow = tree.getRowForPath(dl.getPath());
int[] selRows = tree.getSelectionRows();
if(selRows != null)
{
for(int i = 0; i < selRows.length; i++)
{
if(selRows[i] == dropRow)
return false;
}
}
//Do not allow a drop on a File (leaf)
try
{
TreePath targetPath = tree.getDropLocation().getPath();
DefaultMutableTreeNode node = (DefaultMutableTreeNode) targetPath.getLastPathComponent();
if(node.isLeaf())
{
return false;
}
}
catch(Exception ex)
{
System.out.println(ex.getMessage());
return false;
}
// Do not allow a non-leaf node to be copied to a level
// which is less than its source level.
TreePath dest = dl.getPath();
DefaultMutableTreeNode target = (DefaultMutableTreeNode)dest.getLastPathComponent();
TreePath path = tree.getPathForRow(selRows[0]);
DefaultMutableTreeNode firstNode = (DefaultMutableTreeNode)path.getLastPathComponent();
if(firstNode.getChildCount() > 0 && target.getLevel() < firstNode.getLevel())
{
return false;
}
return true;
}
//Do i have to use exportDone ?
protected void exportDone(JComponent source, Transferable data, int action)
{
if((action & MOVE) == MOVE)
{
//GET THE FILE DESTINATION FOLDER
//LAUNCH THE DOWNLOAD FILE PROCESS
}
}
protected Transferable createTransferable(JComponent c)
{
JTree tree = (JTree)c;
TreePath[] paths = tree.getSelectionPaths();
if(paths != null)
{
// Make up a node array of copies for transfer and
// another for/of the nodes that will be removed in
// exportDone after a successful drop.
ArrayList<DefaultMutableTreeNode> copies = new ArrayList<DefaultMutableTreeNode>();
ArrayList<DefaultMutableTreeNode> toRemove = new ArrayList<DefaultMutableTreeNode>();
//Fake files created in order to allow the export on explorer
ArrayList<File> fakeFiles = new ArrayList<File>();
DefaultMutableTreeNode node = (DefaultMutableTreeNode)paths[0].getLastPathComponent();
DefaultMutableTreeNode copy = copy(node);
copies.add(copy);
toRemove.add(node);
for(int i = 1; i < paths.length; i++)
{
DefaultMutableTreeNode next = (DefaultMutableTreeNode)paths[i].getLastPathComponent();
// Do not allow higher level nodes to be added to list.
if(next.getLevel() < node.getLevel())
{
break;
}
else if(next.getLevel() > node.getLevel())
{ // child node
copy.add(copy(next));
// node already contains child
}
else
{ // sibling
copies.add(copy(next));
toRemove.add(next);
}
}
DefaultMutableTreeNode[] nodesToMove = copies.toArray(new DefaultMutableTreeNode[copies.size()]);
for(DefaultMutableTreeNode n : nodesToMove)
{
File f = new File(n.toString());
fakeFiles.add(f);
}
nodesToRemove = toRemove.toArray(new DefaultMutableTreeNode[toRemove.size()]);
return new NodesTransferable(fakeFiles, Arrays.asList(nodesToMove));
}
return null;
}
/** Defensive copy used in createTransferable. */
private DefaultMutableTreeNode copy(DefaultMutableTreeNode node)
{
return new DefaultMutableTreeNode(node);
}
public int getSourceActions(JComponent c)
{
return COPY_OR_MOVE;
}
public class NodesTransferable implements Transferable
{
private List<File> data = null;
private List<DefaultMutableTreeNode> nodes = null;
private DataFlavor[] flavors = new DataFlavor[2];
public NodesTransferable(final List<File> data, final List<DefaultMutableTreeNode> nodes)
{
super();
this.data = data;
this.nodes = nodes;
flavors[0] = DataFlavor.javaFileListFlavor;
flavors[1] = nodesFlavor;
}
public DataFlavor[] getTransferDataFlavors()
{
return flavors;
}
public boolean isDataFlavorSupported(final DataFlavor flavor)
{
return true;
}
public List<?> getTransferData(final DataFlavor flavor) throws UnsupportedFlavorException, IOException
{
if(flavor.equals(DataFlavor.javaFileListFlavor))
return data;
else if(flavor.equals(nodesFlavor))
return nodes;
else
{
System.out.println("Unsuported flavor");
return null;
}
}
}
}