如何使用Java复制文件并将其粘贴到剪贴板？ [英] How can I copy a file and paste it to the clipboard using Java?

问题描述

如何使用Java复制文件并将其粘贴到剪贴板？我的程序可以复制，但无法粘贴。它给出了

How can I copy a file and paste it to the clipboard using Java? My program can copy but it cannot paste. It gives

线程main中的异常java.lang.ClassCastException：

java.util.Arrays $ ArrayList无法转换为java.io.File

Exception in thread "main" java.lang.ClassCastException:
java.util.Arrays$ArrayList cannot be cast to java.io.File

我的代码：

class FileTransferable implements Transferable {
    private final File file;

    public FileTransferable(File file) {
        this.file = file;
    }

    @Override
    public DataFlavor[] getTransferDataFlavors() {
        return new DataFlavor[] { DataFlavor.javaFileListFlavor };
    }

    @Override
    public boolean isDataFlavorSupported(DataFlavor flavor) {
        return DataFlavor.javaFileListFlavor.equals(flavor);
    }

    @Override
    public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
        final ArrayList<File> files = new ArrayList<File>();
        files.add(file);
        return files;
    }
}

推荐答案

这里是我从DGuitar源代码中获取的完整示例我已根据您的评论删除了自定义或特定详细信息

Here is a full example taken from the DGuitar source code were I have removed the custom or specific Details based on your comment

/*
 * ADropTargetListener
 * Created on 20/04/2005
 *
 *
 */

import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.dnd.DnDConstants;
import java.awt.dnd.DropTargetDragEvent;
import java.awt.dnd.DropTargetDropEvent;
import java.awt.dnd.DropTargetEvent;
import java.awt.dnd.DropTargetListener;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;


/**
 * The Drop action happens in this order: 1. dragEnter =
when the mouse enters
 * the component 2. dragOver = after the mouse has entered
but has not been
 * released 3. drop = when the mouse is released
 * 
 * @author Mauricio Gracia G
 */
public class ADropTargetListener implements DropTargetListener {
    /**
     * creates a DropTargetListener 
     */
    public ADropTargetListener() {

    }

    /**
     * overrides the DROP method.
     * 
     * @see java.awt.dnd.DropTargetListener#drop(java.awt.dnd.DropTargetDropEvent)
     */
    public void drop(DropTargetDropEvent dtde) {
        Transferable transfer;

        transfer = dtde.getTransferable();

        //we must accept the transfer to process it
        dtde.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);

        importData(transfer);
    }
    /**
     * Imports the data of the Drop action
     * @param t the transferable object
     */

    public void importData(Transferable t) {
        if (canImport(t.getTransferDataFlavors())) {
            try {
                DataFlavor[] flavors = t.getTransferDataFlavors();
                for (int i = 0; i < flavors.length; i++) {
                    //       Drop from Windows
                    if (DataFlavor.javaFileListFlavor.equals(flavors[i])) {

                        Object gtd ;

                        gtd = t.getTransferData(DataFlavor.javaFileListFlavor) ;
                        if (gtd instanceof List) {
                            @SuppressWarnings("unchecked")
                            List<File> fileList = (List<File>) gtd;

                                                        //YOUR CODE here to process the list of Files

                        }

                    }
                    //       Drop from GNOME or kde
                    // delimited by \n  (\r\n) on gnome
                    // will need to remove file:// at start
                    else if (DataFlavor.stringFlavor.equals(flavors[i])) {
                        if (t.getTransferData(DataFlavor.stringFlavor)
instanceof String) {
                            String path = (String) t
                                    .getTransferData(DataFlavor.stringFlavor);
                            List<File> fileList = convertStringsToFileList(path);
                            //YOUR CODE here to process the list of Files

                        }

                    }
                }
            } catch (UnsupportedFlavorException e) {
                e.printStackTrace();

            } catch (IOException e) {
                e.printStackTrace();

            }
        }
    }
    /**
     * converts Strings in certain format to a FileList 
     * @param filestr   the list of files in a single string
     * @return          a list of files
     */

    private ArrayList<File> convertStringsToFileList(String filestr) {
        ArrayList<File> files = new ArrayList<File>();
        String[] tokenizedFiles = filestr.split("\n");
        for (int i = 0; i < tokenizedFiles.length; i++) {
            String path = tokenizedFiles[i];
            if (path.startsWith("file://")) {
                if (path.endsWith("\r")) {
                    //appears to be the case for gnome but not kde
                    path = path.substring(7);
                    path = path.replaceAll("\r", "");

                    path = path.replaceAll("%20", " ");
                } else {
                    path = path.substring(7);
                }
            }
            files.add(new File(path));

        }
        return files;
    }
    /**
     * Determine if it can import certain flavor
     * 
     * @param flavors   an array of DataFlavors
     * @return true or not depending on the flavor
     */
    public boolean canImport(DataFlavor[] flavors) {
        for (int i = 0; i < flavors.length; i++) {
            if (DataFlavor.javaFileListFlavor.equals(flavors[i])) {
                return true;
            } else if (DataFlavor.stringFlavor.equals(flavors[i])) {
                return true;
            }
        }
        return false;
    }


    /**
     * method that is called when the drag starts or enters the window
     * @param dtde a DropTargetDragEvent
     * 
     * @see java.awt.dnd.DropTargetListener#dragEnter(java.awt.dnd.DropTargetDragEvent)
     */
    public void dragEnter(DropTargetDragEvent dtde) {
        //DEBUG
        //System.out.println("dragEnter" + ":" + dtde) ;
    }

    /**
     * a method that is called when the DRAG is OVER ??
     * 
     * @see java.awt.dnd.DropTargetListener#dragOver(java.awt.dnd.DropTargetDragEvent)
     */

    public void dragOver(DropTargetDragEvent dtde) {
        //      DEBUG
        //System.out.println("dragOver" + ":" + dtde) ;
    }

    /**
     * when the drop action is changes this method is called
     * 
     * @see java.awt.dnd.DropTargetListener#dropActionChanged(java.awt.dnd.DropTargetDragEvent)
     */
    public void dropActionChanged(DropTargetDragEvent dtde) {
        //      DEBUG
        //System.out.println("dropActionChanged" + ":" + dtde) ;
    }

    /**
     * method called when the drag exits the window
     * 
     * @see java.awt.dnd.DropTargetListener#dragExit(java.awt.dnd.DropTargetEvent)
     */
    public void dragExit(DropTargetEvent dte) {
        //      DEBUG
        //System.out.println("dragExit" + ":" + dte) ;
    }

}

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