CODEWITHSUNDEEP
javaandroidfile-io
ezcoding
ezcoding

Reputation: 2994

FileOutputStream is really slow

I am downloading databases from the network, which are between 100 Kbytes and 500 Kbytes large. Here is my code (removed useless code):

URLConnection uConnection = downloadUrl.openConnection();
InputStream iS = uConnection.getInputStream();
BufferedInputStream bIS = new BufferedInputStream(iS);
byte[] buffer = new byte[1024];
FileOutputStream fOS = new FileOutputStream(db);
int bufferLength = 0;
while ((bufferLength = bIS.read(buffer)) > 0) {
fOS.write(buffer, 0, bufferLength);
}
fOS.close();

My problem is, that it takes a long time for him to finish the while-statement. Have I messed up the code somewhere? It shouldn't take that long for such small files, shouldn't it? I'm talking about 1 minute, for three files not larger than 1 MB altogether... Thanks in advance!

Upvotes: 1

Views: 3694

Answers (2)

Sebastian Dainotti
Sebastian Dainotti

Reputation: 15

I've found the real solution in Jdk 1.7, which is made by reliable, fast, simple and almost definitively will spawn a pity veil on older java.io solutions.Despite the web is still plenty full of examples of copying files in java using In/out Streams I'll warmely suggest everyone to use a simple method : java.nio.Files.copy(Path origin, Path destination) with optional parameters for replacing destination,migrate metadata file attributes and even try a transactional move of files (if permitted by the underlying O.S.). That's a really good Job, waited for so long! You can easily convert code from copy(File file1, File file2) by appending a ".toPath()" to the File instance (e.g. file1.toPath(), file2.toPath(). Note also that the boolean method isSameFile(file1.toPath(), file2.toPath()), is already used inside the above copy method but easily usable in every case you want. For every case you can't upgrade to 1.7 using community libraries from Apache (commons-io) or Google (guava commons) is still suggested.

Upvotes: -3

Brian Roach
Brian Roach

Reputation: 76888

"Slow" is really rather ambiguous. That being said, considering what you're trying to do you shouldn't be using a BufferedInputStream and your buffer is way too small.

The buffered wrappers are for optimizing small reads/writes. Since all you're doing is trying to read a ton of data as fast as you can, you should just read directly from the InputStream, and use a large buffer (Say, 64k since the underlying native code is probably going to chunk at that size anyway). 

byte[] buffer = new byte[65536];
...
while ((bufferLength = iS.read(buffer, 0, buffer.length) > 0) {
    ...

Upvotes: 4

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