java实现zip与unzip

jdk提供了Zip相关的类方便的实现压缩和解压缩。使用方法很简单。下边分别是压缩和解压缩的简单事例
1，压缩的

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import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
public class Zip {
  static final int BUFFER = 2048;
  public static void main(String argv[]) {
    try {
      BufferedInputStream origin = null;
      FileOutputStream dest = new FileOutputStream("E:\\test\\myfiles.zip");
      ZipOutputStream out = new ZipOutputStream(new BufferedOutputStream(dest));
      byte data[] = new byte[BUFFER];
      File f = new File("e:\\test\\a\\");
      File files[] = f.listFiles();
      for (int i = 0; i < files.length; i++) {
        FileInputStream fi = new FileInputStream(files[i]);
        origin = new BufferedInputStream(fi, BUFFER);
        ZipEntry entry = new ZipEntry(files[i].getName());
        out.putNextEntry(entry);
        int count;
        while ((count = origin.read(data, 0, BUFFER)) != -1) {
          out.write(data, 0, count);
        }
        origin.close();
      }
      out.close();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

2，解压缩的。

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import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.util.Enumeration;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
public class UnZip {
  static final int BUFFER = 2048;
  public static void main(String argv[]) {
    try {
      String fileName = "E:\\test\\myfiles.zip";
      String filePath = "E:\\test\\";
      ZipFile zipFile = new ZipFile(fileName);
      Enumeration emu = zipFile.entries();
      int i = 0;
      while (emu.hasMoreElements()) {
        ZipEntry entry = (ZipEntry) emu.nextElement();
        // 会把目录作为一个file读出一次，所以只建立目录就可以，之下的文件还会被迭代到。
        if (entry.isDirectory()) {
          new File(filePath + entry.getName()).mkdirs();
          continue;
        }
        BufferedInputStream bis = new BufferedInputStream(zipFile.getInputStream(entry));
        File file = new File(filePath + entry.getName());
        // 加入这个的原因是zipfile读取文件是随机读取的，这就造成可能先读取一个文件
        // 而这个文件所在的目录还没有出现过，所以要建出目录来。
        File parent = file.getParentFile();
        if (parent != null && (!parent.exists())) {
          parent.mkdirs();
        }
        FileOutputStream fos = new FileOutputStream(file);
        BufferedOutputStream bos = new BufferedOutputStream(fos, BUFFER);
        int count;
        byte data[] = new byte[BUFFER];
        while ((count = bis.read(data, 0, BUFFER)) != -1) {
          bos.write(data, 0, count);
        }
        bos.flush();
        bos.close();
        bis.close();
      }
      zipFile.close();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}