How to create a copy of a file

Question

Is there a method in Java API with which I can create a copy of a file (like running "copy" or "cp" at system command prompt), so that I don't have to use InputStream and OutputStream and create the new file byte by byte?

Answer 1

I would never create an array with the size of the input file. What do you do, if the file is 2GB?
I'd rather use buffered streams: BufferedInputStream in = new BufferedInputStream(new FileInputStream("inputfile.dat"));
BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream("outputfile.dat"));
byte[] buffer = new byte[4096];
int b = in.read(buffer);
while(b>=0)
  out.write(buffer, 0, b);
  b = in.read(buffer);
in.close();
out.close();I'm not sure if using an array to read from a BufferedInputStream really improves performance, but you can play around with it. If you know you have big files, you might want to play with the size of the buffer for the streams as well and see how it affects read/write performance. Setting a larger buffer then the default 64K for the output stream might speed up things.
Thomas