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
线程“main”中的异常java.lang.ClassCastException：
java.util.Arrays $ ArrayList无法强制转换为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;
}
}
答案 0 :(得分：0)
我无法在实际代码中发现任何问题。我想，在您实际接收来自复制/粘贴操作的内容的地方会发生强制转换错误，您将收到一个文件，包含在列表中并且可以投射列表到File。
答案 1 :(得分：0)
以下是从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
/*
* 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) ;
}
}
答案 2 :(得分：-6)
Java无法处理特定的操作系统相关操作，如干扰剪贴板等，因为它是一种独立于平台的语言。在JLS和Java API中，没有剪贴板干扰的方法，但是有一些方法可以处理在Java API中声明的文件系统操作，作为JLS（Java语言规范）的一部分，它在大多数JVM实现中实现。
要做这些事情，你应该使用JNI（Java Native Interface）本地使用C / C ++（使用Win32 API等）开发一些东西，或者使用现成的二进制文件并在Java应用程序中调用它们。