Displaying contents of a compressed zip file

Java provides support to manipulate the compressed zip files. This can be achieved by using classes in java.util.zip package. The ZipFile class of this package represents a compressed zip file and provides methods to get the entries in it. The method, entries() of a ZipFile class, returns the Enumeration of all the entries it contains. The ZipEntry class represents a single entry in the zip file. The ZipEntry object contains all information about a particular entry like; name, size, compressed size, type, etc.

Example Code:

Following example creates a ZipFileViewer, which takes a zip file as parameter and shows its contents in a JTable. The method getZipFileContents(String) of class ZipFileViewer takes a zip file name and returns the List of ZipEntry objects which is used to render the JTable.

/*
 * This example is from javareference.com
 * for more information visit,
 * https://www.javareference.com
 */

import javax.swing.*;
import javax.swing.table.*;
import java.util.*;
import java.util.zip.*;
import java.io.IOException;

/**
 * This class takes a zip file as a parameter
 * and display the contents of this file in a JTable
 *
 * @author Rahul Sapkal([email protected])
 */
public class ZipFileViewer extends JFrame {
  //JTable table
  private JTable m_zipTable;

  //JTable model
  private ZipTableModel m_zipTableModel;

  /**
   * Constructor
   */
  public ZipFileViewer(String zipFile, List zipEntries) {
    //Show the Zip file name and number of items on the title
    super("Zip File Viewer " + "[" + zipFile + "] [" + zipEntries.size() + " Items]");

    //creating the JTable by passing the table model
    m_zipTableModel = new ZipTableModel(zipEntries);

    m_zipTable = new JTable(m_zipTableModel);

    JScrollPane scrollPane = new JScrollPane(m_zipTable);
    m_zipTable.setShowVerticalLines(true);
    m_zipTable.setShowHorizontalLines(false);

    //add the scroll pane to the frame
    getContentPane().add(scrollPane);

    setSize(800, 400);
    setVisible(true);
  }

  /**
   * This method takes the zip file name
   * and returns the List of entries in the zip name
   * That is List of ZipEntry objects
   *
   * @param zipFileName
   * @return List of ZipEntry objects
   */
  public static List getZipFileContents(String zipFileName) {
    ZipFile zipFile = null;
    List zipFileList = null;

    try {
      //create ZipFile object
      zipFile = new ZipFile(zipFileName);

      //get the entries
      Enumeration zipEntries = zipFile.entries();

      zipFileList = new ArrayList();
      while (zipEntries.hasMoreElements()) {
        //add the ZipEntry object to the list
        zipFileList.add((ZipEntry) (zipEntries.nextElement()));
      }
    } catch (ZipException zipExp) {
      System.out.println("Zip Exception: " + zipExp);
    } catch (IOException ioExp) {
      System.err.println("IO Exception: " + ioExp);
    }

    return zipFileList;
  }

  /**
   * Main method to run as an Application
   *
   * @param argv
   */
  public static void main(String[] arg) {
    if (arg.length == 1) {
      String zipFileName = arg[0];
      List zipFileList = getZipFileContents(zipFileName);

      if (zipFileList != null) {
        ZipFileViewer zipFileViewer = new ZipFileViewer(zipFileName, zipFileList);
      } else {
        System.out.println("Cannot Extract File");
      }
    } else {
      System.out.println("Invalid Syntax");
      System.out.println("Usage : java ZipFileViewer <ZipFileName>");
    }
  }

  /**
   * This class is the model for the above JTable
   * It gets data from the ZipEntry object and provides
   * it to the table
   *
   * @author Rahul Sapkal([email protected])
   */
  public class ZipTableModel extends AbstractTableModel {
    //Columns Number.
    public static final int NAME = 0;
    public static final int SIZE = 1;
    public static final int COMP_SIZE = 2;
    public static final int TYPE = 3;
    public static final int LAST_MODI = 4;

    //Names of the columns
    public String[] m_colNames = {"File Name",
            "Size",
            "Compressed Size",
            "Type",
            "Last Modified"};

    private List m_zipEntries;

    /**
     * Constructor
     */
    public ZipTableModel(List zipEntries) {
      super();

      //store the data
      m_zipEntries = zipEntries;
    }

    public int getColumnCount() {
      return m_colNames.length;
    }

    public int getRowCount() {

      return m_zipEntries.size();
    }

    public String getColumnName(int col) {
      return m_colNames[col];
    }

    /**
     * This method gets data from the ZipEntry object
     * and provides it to the table
     */
    public Object getValueAt(int row, int col) {
      ZipEntry zipEntry = (ZipEntry) (m_zipEntries.get(row));
      boolean isDir = zipEntry.isDirectory();

      switch (col) {
        case NAME:
          return zipEntry.getName();
        case SIZE:
          if (isDir) {
            return "";
          } else {
            return String.valueOf(zipEntry.getSize() / 1000) + " KB";
          }
        case COMP_SIZE:
          if (isDir) {
            return "";
          } else {
            return String.valueOf(zipEntry.getCompressedSize() / 1000) + " KB";
          }

        case TYPE:
          if (isDir) {
            return "Directory";
          } else {
            return "File";
          }
        case LAST_MODI:
          return String.valueOf(new Date(zipEntry.getTime()));
      }

      return new String();
    }
  }
  //End ZipTableModel
}
//End ZipFileViewer

Demonstration

Following image shows the ZipFileViewer, when the above program is executed.

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