在Android中以编程方式解压缩文件

Question

I am downloading a zip folder and saving in specific folder in my Android device. My application is not accessing the folder as it is zipped. I would like to unzip the folder after downloading from server and save in specific folder.

And my code is here:

public void DownloadDatabase(String DownloadUrl, String fileName) {
    try {
        File root = android.os.Environment.getExternalStorageDirectory();
        File dir = new File(root.getAbsolutePath() + "/timy/databases");
        if(dir.exists() == false){
             dir.mkdirs();  
        }

        URL url = new URL("http://myexample.com/android/timy.zip");
        File file = new File(dir,fileName);

        long startTime = System.currentTimeMillis();
        Log.d("DownloadManager" , "download url:" +url);
        Log.d("DownloadManager" , "download file name:" + fileName);

        URLConnection uconn = url.openConnection();
        uconn.setConnectTimeout(TIMEOUT_SOCKET);

        InputStream is = uconn.getInputStream();

        ZipInputStream zipinstream = new ZipInputStream(new BufferedInputStream(is));
        ZipEntry zipEntry;

        while((zipEntry = zipinstream.getNextEntry()) != null){
            String zipEntryName = zipEntry.getName();
            File file1 = new File(file + zipEntryName);
            if(file1.exists()){

            }else{
                if(zipEntry.isDirectory()){
                    file1.mkdirs();
                }
            }
        }

        BufferedInputStream bufferinstream = new BufferedInputStream(is);

        ByteArrayBuffer baf = new ByteArrayBuffer(5000);
        int current = 0;
        while((current = bufferinstream.read()) != -1){
            baf.append((byte) current);
        }

        FileOutputStream fos = new FileOutputStream( file);
        fos.write(baf.toByteArray());
        fos.flush();
        fos.close();
        Log.d("DownloadManager" , "download ready in" + ((System.currentTimeMillis() - startTime)/1000) + "sec");
    }
    catch(IOException e) {
        Log.d("DownloadManager" , "Error:" + e);
        e.printStackTrace();
    }

}

And my logcat is showing on error. Just folder is creating in my device and no files are downloading with unzipped. Without using inputZipStream method then my zipped folder is downloading and saving in sdcard. When I want to unzip it, it is not happening.

Answer 1

This article is about how to write a utility class for extracting files and directories in a compressed zip archive, using built-in Java API.

The java.util.zip package provides the following classes for extracting files and directories from a ZIP archive:

ZipInputStream: this is the main class which can be used for reading zip file and extracting files and directories (entries) within the archive. Here are some important usages of this class: -read a zip via its constructor ZipInputStream(FileInputStream) -read entries of files and directories via method getNextEntry() -read binary data of current entry via method read(byte) -close current entry via method closeEntry() -close the zip file via method close()

ZipEntry: this class represents an entry in the zip file. Each file or directory is represented as a ZipEntry object. Its method getName() returns a String which represents path of the file/directory. The path is in the following form: folder_1/subfolder_1/subfolder_2/…/subfolder_n/file.ext

Based on the path of a ZipEntry, we re-create directory structure when extracting the zip file.

Below class is used for unzip download zip and extract file and store your desire location.

  public class UnzipUtil
  {
     private String zipFile;
     private String location;

  public UnzipUtil(String zipFile, String location)
  {
     this.zipFile = zipFile;
     this.location = location;

     dirChecker("");
  }

  public void unzip()
 {
   try
 {
      FileInputStream fin = new FileInputStream(zipFile);
      ZipInputStream zin = new ZipInputStream(fin);
      ZipEntry ze = null;
      while ((ze = zin.getNextEntry()) != null)
      {
       Log.v("Decompress", "Unzipping " + ze.getName());

if(ze.isDirectory())
{
 dirChecker(ze.getName());
}
else
{
 FileOutputStream fout = new FileOutputStream(location + ze.getName());     

 byte[] buffer = new byte[8192];
 int len;
 while ((len = zin.read(buffer)) != -1)
 {
  fout.write(buffer, 0, len);
 }
 fout.close();

 zin.closeEntry();

}

    }
      zin.close();
    }
     catch(Exception e)
     {
          Log.e("Decompress", "unzip", e);
     }

  }

   private void dirChecker(String dir)
   {
         File f = new File(location + dir);
         if(!f.isDirectory())
          {
            f.mkdirs();
          }
         }
    }

MainActivity.Class:

       public class MainActivity extends Activity
        {
        private ProgressDialog mProgressDialog;

        String Url="http://hasmukh/hb.zip";
        String unzipLocation = Environment.getExternalStorageDirectory() + "/unzipFolder/";
        String StorezipFileLocation =Environment.getExternalStorageDirectory() +                       "/DownloadedZip"; 
       String DirectoryName=Environment.getExternalStorageDirectory() + "/unzipFolder/files/";

       @Override
       protected void onCreate(Bundle savedInstanceState)
       {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);

           DownloadZipfile mew = new DownloadZipfile();
            mew.execute(url);

        }

        //-This is method is used for Download Zip file from server and store in Desire location.
        class DownloadZipfile extends AsyncTask<String, String, String>
         {
         String result ="";
          @Override
          protected void onPreExecute()
          {
            super.onPreExecute();
            mProgressDialog = new ProgressDialog(MainActivity.this);
            mProgressDialog.setMessage("Downloading...");
            mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
            mProgressDialog.setCancelable(false);
            mProgressDialog.show();
            }

             @Override
             protected String doInBackground(String... aurl)
             {
              int count;

                    try
          {
URL url = new URL(aurl[0]);
URLConnection conexion = url.openConnection();
conexion.connect();
int lenghtOfFile = conexion.getContentLength();
InputStream input = new BufferedInputStream(url.openStream());

OutputStream output = new FileOutputStream(StorezipFileLocation);

byte data[] = new byte[1024];
long total = 0;

while ((count = input.read(data)) != -1)
{
 total += count;
 publishProgress(""+(int)((total*100)/lenghtOfFile));
 output.write(data, 0, count);
}
output.close();
input.close();
result = "true";

         } catch (Exception e) {

         result = "false";
         }
        return null;

       }
        protected void onProgressUpdate(String... progress)
        {
        Log.d("ANDRO_ASYNC",progress[0]);
        mProgressDialog.setProgress(Integer.parseInt(progress[0]));
        }

         @Override
         protected void onPostExecute(String unused)
         {
               mProgressDialog.dismiss();
               if(result.equalsIgnoreCase("true"))
         {
          try
             {
                unzip();
                   } catch (IOException e)
                   {
                 // TODO Auto-generated catch block
              e.printStackTrace();
              }
                 }
                     else
                   {

                   }
                       }
               }
          //This is the method for unzip file which is store your location. And unzip folder will                 store as per your desire location.



             public void unzip() throws IOException 
            {
            mProgressDialog = new ProgressDialog(MainActivity.this);
            mProgressDialog.setMessage("Please Wait...");
            mProgressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
            mProgressDialog.setCancelable(false);
            mProgressDialog.show();
            new UnZipTask().execute(StorezipFileLocation, DirectoryName);
              }


          private class UnZipTask extends AsyncTask<String, Void, Boolean> 
          {
          @SuppressWarnings("rawtypes")
          @Override
          protected Boolean doInBackground(String... params) 
          {
             String filePath = params[0];
             String destinationPath = params[1];

               File archive = new File(filePath);
                try 
                 {
                 ZipFile zipfile = new ZipFile(archive);
                 for (Enumeration e = zipfile.entries(); e.hasMoreElements();) 
                 {
                         ZipEntry entry = (ZipEntry) e.nextElement();
                         unzipEntry(zipfile, entry, destinationPath);
                    }


         UnzipUtil d = new UnzipUtil(StorezipFileLocation, DirectoryName); 
         d.unzip();

            } 
    catch (Exception e) 
         {
           return false;
         }

          return true;
       }

           @Override
           protected void onPostExecute(Boolean result) 
           {
                mProgressDialog.dismiss(); 

             }


            private void unzipEntry(ZipFile zipfile, ZipEntry entry,String outputDir) throws IOException 
         {

                  if (entry.isDirectory()) 
        {
                createDir(new File(outputDir, entry.getName()));
                return;
          }

           File outputFile = new File(outputDir, entry.getName());
           if (!outputFile.getParentFile().exists())
           {
              createDir(outputFile.getParentFile());
           }

           // Log.v("", "Extracting: " + entry);
          BufferedInputStream inputStream = new BufferedInputStream(zipfile.getInputStream(entry));
          BufferedOutputStream outputStream = new BufferedOutputStream(new FileOutputStream(outputFile));

       try 
        {

         }
       finally 
         {
              outputStream.flush();
              outputStream.close();
              inputStream.close();
          }
           }

             private void createDir(File dir) 
             {
                if (dir.exists()) 
              {
                   return;
                  }
                    if (!dir.mkdirs()) 
                      {
                        throw new RuntimeException("Can not create dir " + dir);
               }
               }}
                 }

            Note: Do not forgot to add below  permission in android Manifest.xml file.

          <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" ></uses-permission>
      <uses-permission android:name="android.permission.INTERNET" />

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Answer 2

Unzip Function

public void unzip(String _zipFile, String _targetLocation) {

    //create target location folder if not exist 
    dirChecker(_targetLocatioan); 

    try { 
        FileInputStream fin = new FileInputStream(_zipFile);
        ZipInputStream zin = new ZipInputStream(fin);
        ZipEntry ze = null;
        while ((ze = zin.getNextEntry()) != null) {

            //create dir if required while unzipping 
            if (ze.isDirectory()) {
                dirChecker(ze.getName());
            } else { 
                FileOutputStream fout = new FileOutputStream(_targetLocation + ze.getName());
                for (int c = zin.read(); c != -1; c = zin.read()) {
                    fout.write(c);
                } 

                zin.closeEntry();
                fout.close();
            } 

        } 
        zin.close();
    } catch (Exception e) {
        System.out.println(e);
    } 
} 

Initialization

ZipManager zipManager = new ZipManager();

zipManager.unzip(inputPath + inputFile, outputPath);

Answer 3

For android, there is a third party library to be used for free.
this library will download your file itself and extract it automatically wherever you want.
you can check this library here.
ExtractionLib for Android