java.util.zip.ZipInputStream类练习

package Flow;
import java.io.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;
import javax.swing.filechooser.FileFilter;

import java.util.*;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
public class ZipTest {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        ZipTestFrame frame = new ZipTestFrame();
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        frame.setVisible(true);
    }

}

class ZipTestFrame extends JFrame{
    private static final int DEFAULT_HEIGHT = 300;
    private static final int DEFAULT_WIDTH = 400;
    private JComboBox fileCombo;
    private JTextArea fileTest;
    private String zipname;

    public ZipTestFrame(){
        setTitle("ZipTest");
        setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
        //add the menu and the Open and Exit items
        JMenuBar menuBar = new JMenuBar();
        JMenu menu = new JMenu("File");

        JMenuItem openItem = new JMenuItem("Open");
        menu.add(openItem);
        openItem.addActionListener(new OpenAction());

        JMenuItem exitItem = new JMenuItem("Exit");
        menu.add(exitItem);
        exitItem.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                System.exit(0);
            }
        });

        menuBar.add(menu);
        setJMenuBar(menuBar);

        //add the text area and combo box
        fileTest = new JTextArea();
        fileCombo = new JComboBox();
        fileCombo.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                loadZipFile((String)fileCombo.getSelectedItem());
            }
        });
        add(fileCombo,BorderLayout.SOUTH);
        add(fileTest,BorderLayout.CENTER);

    }

    /**
     * This is the listener for the file->open menu item
     * @param name
     */
    //////////////////////////////////////////////////
    public class OpenAction implements ActionListener{
        public void actionPerformed(ActionEvent e){
            //prompt the user for a zip file
            JFileChooser chooser = new JFileChooser();
            chooser.setCurrentDirectory(new File("."));
            FileFilter filter = new ExtensionFileFilter();
            ((ExtensionFileFilter) filter).addExtention(".zip");
            ((ExtensionFileFilter) filter).addExtention(".jar");
            ((ExtensionFileFilter) filter).setDescription("ZIP archives");
            chooser.setFileFilter(filter);
            int r = chooser.showOpenDialog(ZipTestFrame.this);
            if(r == JFileChooser.APPROVE_OPTION){
                zipname = chooser.getSelectedFile().getPath();
                //System.out.println(zipname);
                scanZipFile();
            }
        }
    }
    ////////////////////////////////////////////
    /**
     * Scans the contents of the zip archive and populates
     */
    private void scanZipFile() {
        // TODO Auto-generated method stub
        fileCombo.removeAll();
        ZipInputStream zin = null;
        try {
            zin = new ZipInputStream(new FileInputStream(zipname));
            ZipEntry entry = null;
            while((entry = zin.getNextEntry()) != null){
                fileCombo.addItem(entry.getName());

                zin.closeEntry();
            }
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }catch(IOException e1){
            e1.printStackTrace();
        }finally{
            if(zin != null){
                try {
                    zin.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }

    }

    /**
     * Loads a file from the zip archive into the text area
     * @param name the name of the file in the archive
     */
    public void loadZipFile(String name){
        // TODO Auto-generated method stub
        ZipInputStream zin = null;
        try {
            zin = new ZipInputStream(new FileInputStream(zipname));
            ZipEntry entry;
            fileTest.setText("");

            //find entry with matching name in archive
            while((entry = zin.getNextEntry()) != null){
                //read entry with matching name in archive
                BufferedReader in = new BufferedReader(new InputStreamReader(zin));
                String line;
                while((line = in.readLine()) != null){
                    fileTest.append(line);
                    fileTest.append("/n");
                }
            }


        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }catch(IOException e1){
            e1.printStackTrace();
        }finally{
            if(zin != null){
                try {
                    zin.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }
}


class ExtensionFileFilter extends FileFilter{

    private String description = "";
    private ArrayList extensions = new ArrayList();

    public boolean accept(File pathname) {
        // TODO Auto-generated method stub
        if(pathname.isDirectory()){
            return true;
        }
        String name = pathname.getName().toLowerCase();

        //check if the file name ends with any of the extensions
        for(String e : extensions){
            if(name.endsWith(e))
                return true;
        }
            return false;

    }

    /**
     * Sets a description for the file set that this file filter recognizes
     * @param string a description for the file set
     */
    public void setDescription(String string) {
        // TODO Auto-generated method stub
        this.description = string;
    }

    /**
     * Adds an extension that this file Filter recognizes
     * @param string a file extension (suchi as ".txt" or "txt")
     */
    public void addExtention(String string) {
        // TODO Auto-generated method stub
        if(!string.startsWith(".")){
            string = "." + string;
        }
        extensions.add(string.toLowerCase());
    }

    /**
     * Returns a decription for the file set that this file
     * filter recognizes
     * @return a description for the file set
     */
    public String getDescription() {
        // TODO Auto-generated method stub
        return this.description;
    }}

处理ZIP文件的类是在java.util.zip包中而不是在java.io包中。记住啊。

但是呢，ZIP和GZIP类还是java.io.FilteInputStream和java.io.FilterOutputStream的子类。

java.utio.zip包同样也包含了用于计算循环冗余码校验的类。（CRC校验法）。

每个ZIP文件都有文件头，其中包含了诸如文件名和使用的压缩方法等信息。在java中，通过将一个FileInputStream传给ZipInputStream构造器，可以用ZipInputStream类来读取一个ZIP文件。随后需要去查看压缩文件中的每个独立的条目。getNextEntry()方法（恩，很关键的一个方法）可以返回一个描述该条目的ZipEntry类型的对象。（也就是返回一个代表ZIP文件下的一个子文件的类ZipEntry的对象）。ZipInputStream的read方法进行了修改，当达到条目的末尾（不是ZIP文件的末尾哦）时返回-1。随后，必须调用closeEntry()方法来关闭该条目，接着读取下一条目。如上面代码中的一段用来顺序读取ZIP文件条目的代码：

private void scanZipFile() {
        // TODO Auto-generated method stub
        fileCombo.removeAll();
        ZipInputStream zin = null;
        try {
            zin = new ZipInputStream(new FileInputStream(zipname));
            ZipEntry entry = null;
            while((entry = zin.getNextEntry()) != null){
                fileCombo.addItem(entry.getName());

                zin.closeEntry();
            }
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }catch(IOException e1){
            e1.printStackTrace();
        }finally{
            if(zin != null){
                try {
                    zin.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }

    }

要读取ZIP条目的内容（是内容哦，也就是ZIP文件下的文件里的内容），很可能不愿意使用原来的read方法。通常 会使用更适宜的流过滤器的方法。例如，读取ZIP文件中的一个文本文件，可以使用一下循环：

BufferedReader in = new BufferedReader(new InputStreamReader(zin));
String s;
while((s = in.readLine()) != null){
           do something with s;
}

如以上程序中的一段代码：

public void loadZipFile(String name){
        // TODO Auto-generated method stub
        ZipInputStream zin = null;
        try {
            zin = new ZipInputStream(new FileInputStream(zipname));
            ZipEntry entry;
            fileTest.setText("");

            //find entry with matching name in archive
            while((entry = zin.getNextEntry()) != null){
                //read entry with matching name in archive
                BufferedReader in = new BufferedReader(new InputStreamReader(zin));
                String line;
                while((line = in.readLine()) != null){
                    fileTest.append(line);
                    fileTest.append("/n");
                }
            }


        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }catch(IOException e1){
            e1.printStackTrace();
        }finally{
            if(zin != null){
                try {
                    zin.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }
}

当向一个ZIP文件写入时需要打开一个构造器中包含FileOutputStream的ZipOutputStream文件流。对于每一条希望植入ZIP文件的条目，都要创建一个ZipEntry对象。只要把文件名传给ZipEntry构造器，它将会自动设置参数（注意是自动设置哦）。诸如文件日期和压缩方法等等。但是也可以自己覆盖这些参数。对于写出可以查看ZIP，写入会了写出一定是没有问题了。