android 压缩与解压方法

/**
     * 解压缩功能
     * 
     * @throws Exception
     */
     public int upZipFile(File zipFile, String folderPath)throws ZipException,IOException {
     //public static void upZipFile() throws Exception{
         ZipFile zfile=new ZipFile(zipFile);
         Enumeration zList=zfile.entries();
         ZipEntry ze=null;
         byte[] buf=new byte[1024];
         while(zList.hasMoreElements()){
             ze=(ZipEntry)zList.nextElement();    
             if(ze.isDirectory()){
                 String dirstr = folderPath + ze.getName();
                 dirstr = new String(dirstr.getBytes("8859_1"), "GB2312");
                 File f=new File(dirstr);
                 f.mkdir();
                 continue;
             }
             OutputStream os=new BufferedOutputStream(new FileOutputStream(getRealFileName(folderPath, ze.getName())));
             InputStream is=new BufferedInputStream(zfile.getInputStream(ze));
             int readLen=0;
             while ((readLen=is.read(buf, 0, 1024))!=-1) {
                 os.write(buf, 0, readLen);
             }
             is.close();
             os.close();    
         }
         zfile.close();
         return 0;
     }

     /**
     * 给定根目录，返回一个相对路径所对应的实际文件名.
     * @param baseDir 指定根目录
     * @param absFileName 相对路径名，来自于ZipEntry中的name
     * @return java.io.File 实际的文件
 　　*/
     public static File getRealFileName(String baseDir, String absFileName){
         String[] dirs=absFileName.split("/");
         File ret=new File(baseDir);
         String substr = null;
         if(dirs.length>1){
             for (int i = 0; i < dirs.length-1;i++) {
                 substr = dirs[i];
                 try {
                     substr = new String(substr.getBytes("8859_1"), "GB2312");
                     
                 } catch (UnsupportedEncodingException e) {
                     // TODO Auto-generated catch block
                     e.printStackTrace();
                 }
                 ret=new File(ret, substr);
                 
             }
             if(!ret.exists())
                 ret.mkdirs();
             substr = dirs[dirs.length-1];
             try {
                 substr = new String(substr.getBytes("8859_1"), "GB2312");
             } catch (UnsupportedEncodingException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
             ret=new File(ret, substr);
             return ret;
         }
         return ret;
     }