Android解壓縮文件以編程方式在android

Question

我正在下載一個zip文件夾並保存在我的android設備中的特定文件夾中。我的應用程序不能訪問該文件夾，因爲它是壓縮的。我想從服務器下載並解壓後保存在特定文件夾中的文件夾。和我的代碼是在這裏去

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(); 
    } 

} 

和我的logcat出現錯誤。只是文件夾在我的設備中創建，沒有文件正在下載解壓縮... 無法使用inputZipStream方法，然後我的壓縮文件夾正在下載並保存在SD卡中。當我想將它解壓縮，是不會發生..

誰能幫助我克服這個問題..

在此先感謝。

Answer 1

這篇文章是關於如何編寫一個實用程序類，用於使用內置的Java API在壓縮的zip歸檔文件中提取文件和目錄。

java.util.zip包提供下列類用於從ZIP文件中提取文件和目錄：

ZipInputStream：這是可被用於讀取壓縮文件，並提取文件和目錄的主類（條目）。下面是這個類的一些重要用法： - 通過其構造函數讀取ZipInputStream（FileInputStream） - 通過方法讀取文件和目錄條目getNextEntry（） - 通過讀取方法讀取當前條目的二進制數據（字節） - 通過方法關閉當前條目closeEntry（） - 通過close方法關閉zip文件（）

ZipEntry：此類表示zip文件中的條目。每個文件或目錄都被表示爲一個ZipEntry對象。其方法getName（）返回一個表示文件/目錄路徑的字符串。路徑的格式如下： folder_1/subfolder_1/subfolder_2/.../subfolder_n/file.ext

根據ZipEntry的路徑，我們在提取zip文件時重新創建目錄結構。

下面的類是用於解壓縮下載zip和解壓縮文件並存儲您的願望位置。

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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