Convert a BufferedInputStream to a File

Question

I am loading a image from the web to the local android phone. The code that I have for writing to a file is as follows

        BufferedInputStream bisMBImage=null;
        InputStream isImage = null;
        URL urlImage = null;
        URLConnection urlImageCon = null;
        try 
        {
                urlImage = new URL(imageURL); //you can write here any link
                urlImageCon = urlImage.openConnection();
                isImage = urlImageCon.getInputStream();
                bisMBImage = new BufferedInputStream(isImage);

                int dotPos = imageURL.lastIndexOf(".");
                if (dotPos > 0 )
                {
                    imageExt = imageURL.substring(dotPos,imageURL.length());    
                }

                imageFileName = PATH + "t1" + imageExt;
                File file = new File(imageFileName);
                if (file.exists())
                {
                    file.delete();
                    Log.d("FD",imageFileName + " deleted");
                }
                 ByteArrayBuffer baf = new ByteArrayBuffer(255);
                 Log.d("IMAGEWRITE", "Start to write image to Disk");
                 int current = 0;
                 try 
                 {
                    while ((current = bisMBImage.read()) != -1) 
                    {
                             baf.append((byte) current);
                    }

                    FileOutputStream fos = new FileOutputStream(file);
                    fos.write(baf.toByteArray());
                    fos.close();    
                    Log.d("IMAGEWRITE", "Image write to Disk done");
                } 
                catch (IOException e) 
                {
                    e.printStackTrace();
                }                       

                isImage.close();
        } 
        catch (IOException e) 
        {
                Log.d("DownloadImage", "Error: " + e);
        }
        finally
        {
            isImage = null;         
            urlImageCon = null;
            urlImage = null;
        }

For some reason the whole writing to a file takes 1 minute. Is there a way I can optimize this ?

Answer 1

Your buffer is very small: 255 bytes. You could make it 1024 times bigger (255 kilobytes). This is an acceptable size and this would certainly speed up the thing.

Also, this is very slow as it reads the bytes one by one:

while ((current = bisMBImage.read()) != -1)  {
    baf.append((byte) current);
}

You should try using the array version of read() instead: read(byte[] buffer, int offset, int byteCount) with an array as large as what I have described above.

Answer 2

You should use the Android HttpClient for file fetching over the java URL Connection. Also your Buffer is very small. Try this snipped:

FileOutputStream f = new FileOutputStream(new File(root,"yourfile.dat"));

DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet request = new HttpGet(urlString);
HttpResponse response = httpClient.execute(request);
InputStream is = response.getEntity().getContent();

byte[] buffer = new byte[1024];
int len1 = 0;
while ( (len1 = is.read(buffer)) > 0 ) {
        f.write(buffer,0, len1);
}
f.close();