复制目录和文件时需要使用JProgress栏来衡量进度
我有以下代码来复制目录和文件，但不知道在哪里测量进度。 有人可以帮忙吗
至于我在哪里可以测量复制了多少并在JProgress栏中显示它
public static void copy(File src, File dest) throws IOException{ if(src.isDirectory()){ if(!dest.exists()){ //checking whether destination directory exisits dest.mkdir(); System.out.println("Directory copied from " + src + " to " + dest); } String files[] = src.list(); for (String file : files) { File srcFile = new File(src, file); File destFile = new File(dest, file); copyFolder(srcFile,destFile); } }else{ InputStream in = new FileInputStream(src); OutputStream out = new FileOutputStream(dest); byte[] buffer = new byte[1024]; int length; while ((length = in.read(buffer)) > 0){ out.write(buffer, 0, length); } in.close(); out.close(); System.out.println("File copied from " + src + " to " + dest); } 我刚刚为你写了这个实用程序:)（这需要我大约3个小时）：
import java.awt.BorderLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import java.beans.PropertyChangeEvent; import java.beans.PropertyChangeListener; import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.util.List; import javax.swing.BorderFactory; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JOptionPane; import javax.swing.JPanel; import javax.swing.JProgressBar; import javax.swing.JScrollPane; import javax.swing.JTextArea; import javax.swing.JTextField; import javax.swing.SwingUtilities; import javax.swing.SwingWorker; import javax.swing.event.DocumentEvent; import javax.swing.event.DocumentListener; import javax.swing.text.DefaultCaret; public class FileCopierUtility extends JFrame implements ActionListener, PropertyChangeListener { private static final long serialVersionUID = 1L; private JTextField txtSource; private JTextField txtTarget; private JProgressBar progressAll; private JProgressBar progressCurrent; private JTextArea txtDetails; private JButton btnCopy; private CopyTask task; public FileCopierUtility() { buildGUI(); } private void buildGUI() { setTitle("File Copier Utility"); setDefaultCloseOperation(DO_NOTHING_ON_CLOSE); addWindowListener(new WindowAdapter() { @Override public void windowClosing(WindowEvent e) { if(task != null) task.cancel(true); dispose(); System.exit(0); } }); JLabel lblSource = new JLabel("Source Path: "); JLabel lblTarget = new JLabel("Target Path: "); txtSource = new JTextField(50); txtTarget = new JTextField(50); JLabel lblProgressAll = new JLabel("Overall: "); JLabel lblProgressCurrent = new JLabel("Current File: "); progressAll = new JProgressBar(0, 100); progressAll.setStringPainted(true); progressCurrent = new JProgressBar(0, 100); progressCurrent.setStringPainted(true); txtDetails = new JTextArea(5, 50); txtDetails.setEditable(false); DefaultCaret caret = (DefaultCaret) txtDetails.getCaret(); caret.setUpdatePolicy(DefaultCaret.ALWAYS_UPDATE); JScrollPane scrollPane = new JScrollPane(txtDetails, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED); btnCopy = new JButton("Copy"); btnCopy.setFocusPainted(false); btnCopy.setEnabled(false); btnCopy.addActionListener(this); DocumentListener listener = new DocumentListener() { @Override public void removeUpdate(DocumentEvent e) { boolean bEnabled = txtSource.getText().length() > 0 && txtTarget.getText().length() > 0; btnCopy.setEnabled(bEnabled); } @Override public void insertUpdate(DocumentEvent e) { boolean bEnabled = txtSource.getText().length() > 0 && txtTarget.getText().length() > 0; btnCopy.setEnabled(bEnabled); } @Override public void changedUpdate(DocumentEvent e){} }; txtSource.getDocument().addDocumentListener(listener); txtTarget.getDocument().addDocumentListener(listener); JPanel contentPane = (JPanel) getContentPane(); contentPane.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5)); JPanel panInputLabels = new JPanel(new BorderLayout(0, 5)); JPanel panInputFields = new JPanel(new BorderLayout(0, 5)); JPanel panProgressLabels = new JPanel(new BorderLayout(0, 5)); JPanel panProgressBars = new JPanel(new BorderLayout(0, 5)); panInputLabels.add(lblSource, BorderLayout.NORTH); panInputLabels.add(lblTarget, BorderLayout.CENTER); panInputFields.add(txtSource, BorderLayout.NORTH); panInputFields.add(txtTarget, BorderLayout.CENTER); panProgressLabels.add(lblProgressAll, BorderLayout.NORTH); panProgressLabels.add(lblProgressCurrent, BorderLayout.CENTER); panProgressBars.add(progressAll, BorderLayout.NORTH); panProgressBars.add(progressCurrent, BorderLayout.CENTER); JPanel panInput = new JPanel(new BorderLayout(0, 5)); panInput.setBorder(BorderFactory.createCompoundBorder(BorderFactory.createTitledBorder("Input"), BorderFactory.createEmptyBorder(5, 5, 5, 5))); JPanel panProgress = new JPanel(new BorderLayout(0, 5)); panProgress.setBorder(BorderFactory.createCompoundBorder(BorderFactory.createTitledBorder("Progress"), BorderFactory.createEmptyBorder(5, 5, 5, 5))); JPanel panDetails = new JPanel(new BorderLayout()); panDetails.setBorder(BorderFactory.createCompoundBorder(BorderFactory.createTitledBorder("Details"), BorderFactory.createEmptyBorder(5, 5, 5, 5))); JPanel panControls = new JPanel(new BorderLayout()); panControls.setBorder(BorderFactory.createEmptyBorder(5, 0, 5, 0)); panInput.add(panInputLabels, BorderLayout.LINE_START); panInput.add(panInputFields, BorderLayout.CENTER); panProgress.add(panProgressLabels, BorderLayout.LINE_START); panProgress.add(panProgressBars, BorderLayout.CENTER); panDetails.add(scrollPane, BorderLayout.CENTER); panControls.add(btnCopy, BorderLayout.CENTER); JPanel panUpper = new JPanel(new BorderLayout()); panUpper.add(panInput, BorderLayout.NORTH); panUpper.add(panProgress, BorderLayout.SOUTH); contentPane.add(panUpper, BorderLayout.NORTH); contentPane.add(panDetails, BorderLayout.CENTER); contentPane.add(panControls, BorderLayout.SOUTH); pack(); setLocationRelativeTo(null); } @Override public void actionPerformed(ActionEvent e) { if("Copy".equals(btnCopy.getText())) { File source = new File(txtSource.getText()); File target = new File(txtTarget.getText()); if(!source.exists()) { JOptionPane.showMessageDialog(this, "The source file/directory does not exist!", "ERROR", JOptionPane.ERROR_MESSAGE); return; } if(!target.exists() && source.isDirectory()) target.mkdirs(); else { int option = JOptionPane.showConfirmDialog(this, "The target file/directory already exists, do you want to overwrite it?", "Overwrite the target", JOptionPane.YES_NO_OPTION); if(option != JOptionPane.YES_OPTION) return; } task = this.new CopyTask(source, target); task.addPropertyChangeListener(this); task.execute(); btnCopy.setText("Cancel"); } else if("Cancel".equals(btnCopy.getText())) { task.cancel(true); btnCopy.setText("Copy"); } } @Override public void propertyChange(PropertyChangeEvent evt) { if("progress".equals(evt.getPropertyName())) { int progress = (Integer) evt.getNewValue(); progressAll.setValue(progress); } } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { @Override public void run() { new FileCopierUtility().setVisible(true); } }); } class CopyTask extends SwingWorker { private File source; private File target; private long totalBytes = 0L; private long copiedBytes = 0L; public CopyTask(File source, File target) { this.source = source; this.target = target; progressAll.setValue(0); progressCurrent.setValue(0); } @Override public Void doInBackground() throws Exception { txtDetails.append("Retrieving some info ... "); retrieveTotalBytes(source); txtDetails.append("Done!\n"); copyFiles(source, target); return null; } @Override public void process(List chunks) { for(int i : chunks) { progressCurrent.setValue(i); } } @Override public void done() { setProgress(100); btnCopy.setText("Copy"); } private void retrieveTotalBytes(File sourceFile) { File[] files = sourceFile.listFiles(); for(File file : files) { if(file.isDirectory()) retrieveTotalBytes(file); else totalBytes += file.length(); } } private void copyFiles(File sourceFile, File targetFile) throws IOException { if(sourceFile.isDirectory()) { if(!targetFile.exists()) targetFile.mkdirs(); String[] filePaths = sourceFile.list(); for(String filePath : filePaths) { File srcFile = new File(sourceFile, filePath); File destFile = new File(targetFile, filePath); copyFiles(srcFile, destFile); } } else { txtDetails.append("Copying " + sourceFile.getAbsolutePath() + " ... "); BufferedInputStream bis = new BufferedInputStream(new FileInputStream(sourceFile)); BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(targetFile)); long fileBytes = sourceFile.length(); long soFar = 0L; int theByte; while((theByte = bis.read()) != -1) { bos.write(theByte); setProgress((int) (copiedBytes++ * 100 / totalBytes)); publish((int) (soFar++ * 100 / fileBytes)); } bis.close(); bos.close(); publish(100); txtDetails.append("Done!\n"); } } } }
要实现此目的，您必须提前计算复制操作的数量。 您没有包含copyFolder方法，但我认为您希望执行递归复制。 如果是这样，您必须遍历整个目录树以确定要复制的文件数。 在处理大型目录结构时，这会让用户感到讨厌。 （这就是为什么现代操作系统经常显示恼人的“准备复制……” – 操作开始之前的消息并显示进度）
显示文件的进度非常简单……
long expectedBytes = src.length(); // This is the number of bytes we expected to copy.. byte[] buffer = new byte[1024]; int length; long totalBytesCopied = 0; // This will track the total number of bytes we've copied while ((length = in.read(buffer)) > 0){ out.write(buffer, 0, length); totalBytesCopied += length; int progress = (int)Math.round(((double)totalBytesCopied / (double)expectedBytes) * 100); setProgress(progress); // From SwingWorker }
如果要提供有关要复制/已开始复制的总字节数的信息，则会变得有点复杂。
你有选择。 您要么预先扫描所有文件夹（我将文件放入某种队列）并计算要复制的文件的总字节数/数量。 然后开始实际的复制过程。
更新此进程就像之前的示例一样简单，除了您要累积在整个进程而不是单个文件上复制的总字节数。
要么…
您可以使用生产者/消费者算法。 我们的想法是创建一个线程/工作者，其唯一的职责是扫描文件夹以查找要复制的文件，并将它们放入中央/共享队列（这是生产者）。
你会有第二个线程/工作者弹出这个队列的下一个项目（阻塞到一个新的文件变得可用），并实际上将复制该文件。
这里的技巧是让队列维持一个计数器，使其与通过它的文件和字节总数保持一致，这样你就可以调整总工作的持续进度…