關于java解壓縮文件（rar或者zip）的實現示例

注意：需要用到第三方jar包ant-1.6.5.jar，實際用到的是其中的zip下類。

代碼如下：

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import org.apache.tools.zip.ZipEntry;
import org.apache.tools.zip.ZipFile;
import org.apache.tools.zip.ZipOutputStream;

/**
 * <p>
 * Title: 解壓縮文件
 * </p>
 * <p>
 * Description: 通過apache的zip工具實現解壓縮
 * </p>
 * <p>
 * Copyright: Copyright (c) 2010
 * </p>
 * <p>
 * Company: yourcompany
 * </p>
 * 
 * @author yourcompany
 * @version 1.0
 */
public class CompressFile {
 private static CompressFile instance = new CompressFile();

 private CompressFile() {
 }

 public static CompressFile getInstance() {
  return instance;
 }

 /**
  * 壓縮文件或者文件目錄到指定的zip或者rar包
  * 
  * @param inputFilename
  *            要壓縮的文件或者文件夾，如果是文件夾的話，會將文件夾下的所有文件包含子文件夾的內容進行壓縮
  * @param zipFilename
  *            生成的zip或者rar文件的名稱
  */
 public synchronized void zip(String inputFilename, String zipFilename)
   throws IOException {
  zip(new File(inputFilename), zipFilename);
 }

 /**
  * 壓縮文件或者文件目錄到指定的zip或者rar包，內部調用
  * 
  * @param inputFile
  *            參數為文件類型的要壓縮的文件或者文件夾
  * @param zipFilename
  *            生成的zip或者rar文件的名稱
  * @return void
  */
 private synchronized void zip(File inputFile, String zipFilename)
   throws IOException {
  ZipOutputStream out = new ZipOutputStream(new FileOutputStream(
    zipFilename));

  try {
   zip(inputFile, out, "");
  } catch (IOException e) {
   throw e;
  } finally {
   out.close();
  }
 }

 /**
  * 壓縮文件或者文件目錄到指定的zip或者rar包
  * 
  * @param inputFile
  *            參數為文件類型的要壓縮的文件或者文件夾
  * @param out
  *            輸出流
  * @param base
  *            基文件夾
  * @return void
  */
 private synchronized void zip(File inputFile, ZipOutputStream out,
   String base) throws IOException {
  if (inputFile.isDirectory()) {
   File[] inputFiles = inputFile.listFiles();
   out.putNextEntry(new ZipEntry(base + "/"));
   base = base.length() == 0 ? "" : base + "/";
   for (int i = 0; i < inputFiles.length; i++) {
    zip(inputFiles[i], out, base + inputFiles[i].getName());
   }

  } else {
   if (base.length() > 0) {
    out.putNextEntry(new ZipEntry(base));
   } else {
    out.putNextEntry(new ZipEntry(inputFile.getName()));
   }

   FileInputStream in = new FileInputStream(inputFile);
   try {
    int c;
    byte[] by = new byte[BUFFEREDSIZE];
    while ((c = in.read(by)) != -1) {
     out.write(by, 0, c);
    }
   } catch (IOException e) {
    throw e;
   } finally {
    in.close();
   }
  }
 }

 /**
  * 解壓zip或者rar包的內容到指定的目錄下，可以處理其文件夾下包含子文件夾的情況
  * 
  * @param zipFilename
  *            要解壓的zip或者rar包文件
  * @param outputDirectory
  *            解壓后存放的目錄
  */
 public synchronized void unzip(String zipFilename, String outputDirectory)
   throws IOException {
  File outFile = new File(outputDirectory);
  if (!outFile.exists()) {
   outFile.mkdirs();
  }

  ZipFile zipFile = new ZipFile(zipFilename);
  Enumeration en = zipFile.getEntries();
  ZipEntry zipEntry = null;
  while (en.hasMoreElements()) {
   zipEntry = (ZipEntry) en.nextElement();
   if (zipEntry.isDirectory()) {
    // mkdir directory
    String dirName = zipEntry.getName();
    // System.out.println("=dirName is:=" + dirName + "=end=");
    dirName = dirName.substring(0, dirName.length() - 1);
    File f = new File(outFile.getPath() + File.separator + dirName);
    f.mkdirs();
   } else {
    // unzip file
    String strFilePath = outFile.getPath() + File.separator
      + zipEntry.getName();
    File f = new File(strFilePath);

    // the codes remedified by can_do on 2010-07-02 =begin=
    // /////begin/////
    // 判斷文件不存在的話，就創建該文件所在文件夾的目錄
    if (!f.exists()) {
     String[] arrFolderName = zipEntry.getName().split("/");
     String strRealFolder = "";
     for (int i = 0; i < (arrFolderName.length - 1); i++) {
      strRealFolder += arrFolderName[i] + File.separator;
     }
     strRealFolder = outFile.getPath() + File.separator
       + strRealFolder;
     File tempDir = new File(strRealFolder);
     // 此處使用.mkdirs()方法，而不能用.mkdir()
     tempDir.mkdirs();
    }
    // /////end///
    // the codes remedified by can_do on 2010-07-02 =end=
    f.createNewFile();
    InputStream in = zipFile.getInputStream(zipEntry);
    FileOutputStream out = new FileOutputStream(f);
    try {
     int c;
     byte[] by = new byte[BUFFEREDSIZE];
     while ((c = in.read(by)) != -1) {
      out.write(by, 0, c);
     }
     // out.flush();
    } catch (IOException e) {
     throw e;
    } finally {
     out.close();
     in.close();
    }
   }
  }
 }

 private static final int BUFFEREDSIZE = 1024;

 public static void main(String[] args) {
  CompressFile bean = new CompressFile();
  try {
   boolean isZip = false;
   if (isZip) {
    bean.zip("E:\\20100707", "d:/test_rar.zip");
   } else {
    bean.unzip("d:/test_rar.zip", "D:/temp");
   }
  } catch (IOException e) {
   e.printStackTrace();
  }
 }

}