Java zip程序产生损坏的zip文件

Question

我想用Java编写一个GUI zip/unzip程序。该程序将能够压缩文件和目录/IES的任何组合，并解压缩一个或多个压缩文件。

现在我刚刚完成了GUI和zip Funtion。但是zip funtion似乎不能正常工作，产生的zip文件不知何故被破坏了。我找不到问题到底出在哪里。它似乎与compress函数或zipfile函数有关。

当我测试该程序时，输出如下：

归档：找不到test1.zip中央目录结束签名。要么这个文件不是zipfile，要么它构成了多部分归档的一个磁盘。在后一种情况下，中央目录和zipfile注释将在这个归档的最后一个磁盘上找到。

解压缩：在test1.zip或test1.zip.zip中找不到zipfile目录，也找不到test1.zip.zip，句点。

非常感谢你的帮助。

package javazip;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.TitledBorder;
import javax.swing.filechooser.FileFilter;
import java.io.*;
import java.util.zip.*;

public class JZip {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable () {
            public void run () {
                new JZipFrame();
            }
        });
    }
}

class JZipFrame extends JFrame {
    private JTextArea displayArea;

    public JZipFrame () {
        setTitle("JZip");
        Toolkit tk = Toolkit.getDefaultToolkit();
        Dimension screenSize = tk.getScreenSize();
        int screenHeight = screenSize.height;
        int screenWidth = screenSize.width;
        setSize(screenWidth / 4, screenHeight / 4);
        setLocation(screenWidth / 4, screenHeight / 4);
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        JMenuBar menuBar = createMenuBar();
        JScrollPane displayPanel = createDisplayPanel();

        add(displayPanel);
        setJMenuBar(menuBar);

        setVisible(true);
    } 

    private JMenuBar createMenuBar () {
        JMenuBar menuBar = new JMenuBar();
        JMenu menu = new JMenu("Operations");
        JMenuItem compressItem = createCompressItem();
        JMenuItem decompressItem = createDecompressItem();
        JMenuItem quitItem = createQuitItem();

        menu.add(compressItem);
        menu.add(decompressItem);
        menu.add(quitItem);
        menuBar.add(menu);

        return menuBar;
    }

    private JScrollPane createDisplayPanel () {
        displayArea = new JTextArea(20, 40);
        displayArea.setMargin(new Insets(5, 5, 5, 5));
        displayArea.setEditable(false);
        JScrollPane scrlPanel = new JScrollPane(displayArea);

        return scrlPanel;
    }

    private JMenuItem createCompressItem () {
        JMenuItem cItem = new JMenuItem("Compression");
        cItem.addActionListener(new ActionListener () {
            public void actionPerformed (ActionEvent event) {
                File[] cChosenItems = selectFilesForCompression();
                compress(cChosenItems);
            }
        });

        return cItem;
    }

    private JMenuItem createDecompressItem () {
        JMenuItem dItem = new JMenuItem("Decompression");
        dItem.addActionListener(new ActionListener () {
            public void actionPerformed (ActionEvent event) {
                File[] dChosenItems = selectFilesForDecompression();
                decompress(dChosenItems);
            }
        });

        return dItem;
    }

    private final File[] selectFilesForCompression () {
        final JFileChooser cChooser = new JFileChooser();
        File[] selectedItems = null;

        cChooser.setMultiSelectionEnabled(true);
        cChooser.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
        int cRetVal = cChooser.showOpenDialog(JZipFrame.this);
        if (cRetVal == JFileChooser.APPROVE_OPTION) {
            selectedItems = cChooser.getSelectedFiles();
            for (File item : selectedItems)
                displayArea.append(item.getParent() + System.getProperty("file.separator") 
                                        + item.getName() + "\n");
        }
        return selectedItems;
    }

    private final File[] selectFilesForDecompression () {
        final JFileChooser dChooser = new JFileChooser();
        dChooser.setMultiSelectionEnabled(true);
        dChooser.setFileSelectionMode(JFileChooser.FILES_ONLY);
        dChooser.addChoosableFileFilter(new FileFilter() {
            public String getDescription () {
                return "ZIP Files (*.zip)";
            }
            public boolean accept (File f) {
                if (f.isDirectory())
                    return true;
                else 
                    return f.getName().toLowerCase().endsWith(".zip");
            }
        });
        int dRetVal = dChooser.showOpenDialog(JZipFrame.this);
        File[] selectedItems = null;

        if (dRetVal == JFileChooser.APPROVE_OPTION) {
            selectedItems = dChooser.getSelectedFiles();
            for (File item : selectedItems)
                displayArea.append(item.getParent() + System.getProperty("file.separator") 
                                        + item.getName() + "\n");
        }
        return selectedItems;
    }

    private JMenuItem createQuitItem () {
        JMenuItem qItem = new JMenuItem("Quit");
        qItem.addActionListener(new ActionListener () {
            @Override
            public void actionPerformed (ActionEvent event) {
                System.exit(0);
            }
        });
        return qItem;
    }

    private final void compress (File[] files) {
        FileOutputStream out = null;
        String zipName = null;

        if (files.length == 1) {
            zipName = files[0].getName();
            if (files[0].isDirectory()) {
                if (zipName.endsWith("/") || zipName.endsWith("\\"))
                    zipName = zipName.substring(0, zipName.length() - 1);
            }
            try {
                String name = zipName.substring(0, zipName.lastIndexOf("."));
                out = new FileOutputStream(name + ".zip");
            }
            catch (FileNotFoundException e) {
                JOptionPane.showMessageDialog(this, e.toString(), "Error", JOptionPane.ERROR_MESSAGE);
            }
        }
        else {
            try {
                out = new FileOutputStream(files[0].getParent() + "/compressed.zip");
            }
            catch (FileNotFoundException e) {
                JOptionPane.showMessageDialog(this, e.toString(), "Error", JOptionPane.ERROR_MESSAGE);
            }
        }
        ZipOutputStream zipOut = new ZipOutputStream(out);
        zipOut.setMethod(ZipOutputStream.DEFLATED);
        for (File f : files) {
            try {
                zipFile(f, f.getName(), zipOut);    
            }
            catch (IOException e) {
                JOptionPane.showMessageDialog(this, e.toString(), "Error", JOptionPane.ERROR_MESSAGE);
            }
            displayArea.append("Now processing: " + f.getName() + "\n");
        }
        JOptionPane.showMessageDialog(this, "Compression was successful!", "Message", JOptionPane.INFORMATION_MESSAGE);
    }
    // The problem may be with this function or the one above
    private void zipFile (File file, String fileName, ZipOutputStream zipOut) throws IOException {

        if (file.isHidden()) {
            return;
        }
        if (file.isDirectory()) {
            if (fileName.endsWith("/") || fileName.endsWith("\\")) {
                zipOut.putNextEntry(new ZipEntry(fileName));
                zipOut.closeEntry();
            }
            else {
                zipOut.putNextEntry(new ZipEntry(fileName + "/"));
                zipOut.closeEntry();
            }
            File[] children = file.listFiles();
            for (File childFile : children)
                zipFile(childFile, fileName + "/" + childFile.getName(), zipOut);

            return;
        }
        FileInputStream input = new FileInputStream(file);
        ZipEntry zipEntry = new ZipEntry(fileName);
        zipOut.putNextEntry(zipEntry);
        byte[] bytes = new byte[1024];
        int length;
        while ((length = input.read(bytes)) >= 0) {
            zipOut.write(bytes, 0, length);
        }
        input.close();
    } 

    private final void decompress (File[] files) {
        // TODO
    }
}

Answer 1

在web上摸索之后，我找到了一个关于ZipoutStream的教程，在其中我注意到ZipoutPutStream对象在压缩操作后被关闭。因此，我添加了代码来关闭ZipoutputStream对象，即在我的代码中的compress方法中的zipout。代码现在可以正确地压缩单个文件、多个文件、目录以及文件和目录/IES的组合。

因此，在使用输入流和输出流对象时，一定要记得在使用后关闭它们。否则缓冲区将无法正确地读取或写入以产生所需的结果。

现在，我将继续编写decompress方法，并可能添加更多特性。我可能还会遇到问题，到那时我会来这里寻求帮助。这里的Peeple很有帮助，解决了我的很多问题。非常感谢你的帮助。