I wrote an android application that part of it is to handle upload and download documents. Currently I am using the Microsoft Azure server to save the files on.
The way I am currently doing it is by turning the files to a string and saving it that way on the Azure server:
ByteArrayOutputStream baos = new ByteArrayOutputStream();
FileInputStream fis;
try {
fis = new FileInputStream(new File(Uridata.getPath()));
byte[] buf = new byte[1024];
int n;
while (-1 != (n = fis.read(buf)))
baos.write(buf, 0, n);
} catch (Exception e) {
e.printStackTrace();
}
byte[] bbytes = baos.toByteArray();
item.setStringFile(Base64.encodeToString(bbytes, Base64.URL_SAFE));
item.setName(Uridata.getLastPathSegment());
where item is my class that saves the string representation and the name of the file and is being loaded to the Azure, Uridata is an Uri instance of the file chosen.
I have one main problem with this solution and it is the limit on the file size.
I am searching for a good server to use instead of the Azure (maybe a RESET one) and if there is a better way to save files of all kinds (pdf, word...).
I will also want in the future to use the same data in a web interface
Does anybody have any suggestions on how to do it?
Thanks in advance!
To start, you don't have to transform the file into a string, you can just save it as a file. You have the possibility of losing data by continuing to do that. See: How do I save a stream to a file in C#?
If you're looking for another service to save files, then you should look into Azure Blob Storage. It will allow you to upload as much data as you want to a storage service for arbitrary files. See for example:
https://azure.microsoft.com/en-us/documentation/articles/storage-dotnet-how-to-use-blobs/
Related
I have pictures to send to a server from an android device.
I'm trying to find out which is perhaps better as a storage option.
I'm struggling to see which format will use less storage space on the device and server. I am already sending data(text) from Db's over to server.
So wondering if it's best to put the pictures as byte arrays into db (stored and sent) seeing as I have Db's already
OR
Keep the pic's out of db and send separate.
i hope this helps you
public byte[] extractBytes (String ImageName) throws IOException {
File imgPath = new File(ImageName);
BufferedImage bufferedImage = ImageIO.read(imgPath);
WritableRaster raster = bufferedImage .getRaster();
DataBufferByte data = (DataBufferByte) raster.getDataBuffer();
return ( data.getData() );
}
I have an app that needs to implement a 'share' option to transfer data contained in the device's local database to another device, where that device can take this data and insert it into the appropriate tables in the device's database.
I have communication working over bluetooth, I'm just looking for a good way to transfer this data across. Is there an easy way to do an sqlite dump on device A, transfer this across to device B using bluetooth, and have device B reinsert this data?
Implementing aContentProvider is how you leverage the Android framework to do CRUD operations on a database.
A good way could be to transform a row into Json and unpackage that string on the receiving side to insert it. This way is more testable, easier to recover from errors during send, but might be very slow depending on the size of your data. For speeding it up I would send multiple rows in batches and test to see what batch size would be best for speed and reliability.
A fast way might be to dump the data to flat file then use the FileProvider to provide access to that file as a URI and try something like the following from here
public void sendFile(Uri uri, BluetoothSocket bs) throws IOException {
BufferedInputStream bis = new BufferedInputStream(getContentResolver().openInputStream(uri));
OutputStream os = bs.getOutputStream();
try {
int bufferSize = 1024;
byte[] buffer = new byte[bufferSize];
// we need to know how may bytes were read to write them to the byteBuffer
int len = 0;
while ((len = bis.read(buffer)) != -1) {
os.write(buffer, 0, len);
}
} finally {
bis.close();
os.flush();
os.close();
bs.close();
}
}
My android program crashes on this line when the file size is very large. Is there any way I can prevent the program from crashing ?
byte[] myByteArray = new byte[(int)mFile.length()];
Additional details :-
I am trying to send a file to server.
error log-
E/dalvikvm-heap(29811): Out of memory on a 136309996-byte allocation.
You should use a stream when reading the file. Since you've mentioned sending to a server, you should stream that file to the server.
As others have mentioned, you should consider your data size (1GB seems excessive). I haven't tested this, but the basic approach in code would look something like:
// open a stream to the file
FileInputStream fileInputStream = new FileInputStream(filePath);
// open a stream to the server
HttpURLConnection connection = new URL(url).openConnection();
DataOutputStream outputStream = new DataOutputStream(connection.getOutputStream());
byte[] buffer = new byte[BUFFER_SIZE]; // pick some buffer size
int bytesRead = 0;
// continually read from the file into the buffer and immediately write that to output stream
while ((bytesRead = fileInputStream.read(buffer)) != -1) {
outputStream.write(buffer);
}
Hope that is clear enough for you to fit to your needs.
Yep. Don't try to read the whole file into memory at once...
If you really need the whole file in memory you might have more luck with allocating dynamic memory for each line and storing the lines in a list. (you might be able to get a bunch of smaller chunks of memory but not one big piece)
Without knowing the context we can't tell, but normally you would parse the file into data structs rather than just storing the whole file in memory.
In JDK 7 you can use Files.readAllBytes(Path).
Example:
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.Path;
Path path = Paths.get("path/to/file");
byte[] myByteArray = Files.readAllBytes(path);
Don't try reading the complete file into memory. Instead open a stream and process the file line by line (is it's a text file) or in parts. How that has to be done depends on the problem you are trying to solve.
EDIT: You say you want to upload a file, so please check this question. You don't need to have the complete file in memory.
I want to download PDF's and images into my app, essentially it will call a JSON web service that returns the link to the PDF, link to the image, and the title. It will download the image and PDF and save them. Then it will display the PDF's and images with the title. My only question is how do I deal with images? They cant be saved to APK since it is locked. The images are high enough resolution that they can scaled down to fit all the other densities, should I just use the large image, and let the activity scale it down when it uses it. Or should I implement an image scaler during the retrieval process?
Eventually the PDF's and images would be loaded into the APK. How would I check the assets folder to remove the images, would I just need to call a service that runs when the Application First starts to check for the files in the assets folder then remove them if they are present?
Sample code for your reference where u can download Images from the web.Its better to store Images in asset folder than Internal Memory and resize the images for good performance.U can delete the folder before making web service call and load new set images.
if (Utility.isWifiPresent()
|| Utility.isMobileConnectionPresent()) {
URL url = new URL(fileUrl);
InputStream iStream = url.openConnection().getInputStream();// .read(data)
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
byte[] tmpArray = new byte[1024];
int nRead;
while ((nRead = iStream.read(tmpArray, 0, tmpArray.length)) != -1) {
buffer.write(tmpArray, 0, nRead);
}
buffer.flush();
data = buffer.toByteArray();
FileOutputStream fOut = null;
//path to store
fOut = Utility.getFileOutputStreamForCloud(
sdcardFolderPath, fileUrl);
}
fOut.write(data);
fOut.flush();
fOut.close();
hi all:
making a sample application in which we can store data on File and then could Read it.,
m using the following code.:
Code to Write:
OutputStreamWriter out = null;
try {
out = new OutputStreamWriter(openFileOutput("finear.fin", 0));
out.write(data); //data is String variable
out.close();
Toast.makeText(getApplicationContext(), "Data has been Saved! ", Toast.LENGTH_LONG).show();
}
Code to Read:
instream = openFileInput("finear.fin");
if(instream!=null)
{
InputStreamReader inputReader = new InputStreamReader(instream);
BufferedReader buffreader = new BufferedReader(inputReader);
String dataRead = buffreader.readLine();
}
Now problem is: The Data is stored in simple Text Form but i want that no one could read my data from that file and it should store the data in some binary form or some symbols type format so that when one opens the file in windows it should not display my text stored in the file or should display some other data.. BUT also that data could be readable in String form when i read. PLease Help
You can use Android's internal storage, which is private to your application:
You can save files directly on the device's internal storage. By default, files saved to the internal storage are private to your application and other applications cannot access them (nor can the user). When the user uninstalls your application, these files are removed.
Here you can find the docs: http://developer.android.com/guide/topics/data/data-storage.html#filesInternal
Encrypt the String before saving it to the stream and the other way to read it. If you want your file's contents to be unreadable, encryption would be a win.