Does java.nio.FileChannel automatically buffer writes?

[robertjparks]

Hi, I am using java.nio.FileChannel to write out very large files. Each
call to channel.write() only writes a few bytes at a time. Will my
program run faster if I build up a large ByteBuffer before calling
channel.write() or do FileChannels automatically buffer for you?

Thanks for your help!
Rob

 

[Andrey Kuznetsov]

Hi, I am using java.nio.FileChannel to write out very large files. Each

call to channel.write() only writes a few bytes at a time. Will my
program run faster if I build up a large ByteBuffer before calling
channel.write() or do FileChannels automatically buffer for you?

no auto buffering.
You have to use your own buffer.
Say from 50 till 512 KB is ok.
Unified I/O could make buffering for you, however it does not work with
Channels.

Andrey

 

[Andrey Kuznetsov]

Hi, I am using java.nio.FileChannel to write out very large files. Each

no auto buffering.
You have to use your own buffer.
Say from 50 till 512 KB is ok.
Unified I/O could make buffering for you, however it does not work with
Channels.

see also http://uio.imagero.com/performance.html

Andrey