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Groups > comp.lang.java.programmer > #21772
| From | Knute Johnson <nospam@knutejohnson.com> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: The first 10 files |
| Date | 2013-01-26 18:37 -0800 |
| Organization | A noiseless patient Spider |
| Message-ID | <ke23sm$afb$1@dont-email.me> (permalink) |
| References | <mn.d04a7dd156c148ef.70216@a.com> |
On 1/26/2013 1:14 AM, Wojtek wrote:
> Using:
>
> int max = 10;
> int count = 0;
>
> for (File thisFile : aDir.listFiles())
> {
> doSomething(thisFile);
>
> if ( ++count >= max )
> break;
> }
>
> gives me the first ten files in aDir. But if aDir contains 30K files,
> then the listFiles() will run for a long time as it builds an array for
> the 30K files.
>
> Is there a way to have Java only get the first "max" files?
>
import java.io.*;
import java.nio.*;
import java.nio.file.*;
public class FileSystemsTest {
public static void main(String[] args) throws IOException {
long start = System.currentTimeMillis();
Path dir = FileSystems.getDefault().getPath(".");
int i=10;
DirectoryStream<Path> stream = Files.newDirectoryStream(dir);
for (Path path : stream) {
System.out.println(path.getFileName());
if (--i <= 0)
break;
}
long stop = System.currentTimeMillis();
System.out.println(stop - start);
}
}
300003 files in the directory, almost 1.7GB of files, Windows XP, Java 7
and it takes 16 ms to run. Somebody else should try this out on their
computer to see if it works as fast.
.
.
.
01/26/2013 05:46 PM 58,890 9998.txt
01/26/2013 05:46 PM 58,890 9999.txt
01/26/2013 06:31 PM 1,316 FileSystemsTest.class
01/26/2013 06:29 PM 636 FileSystemsTest.java
01/26/2013 05:44 PM 650 MakeFiles.java
30003 File(s) 1,766,702,602 bytes
2 Dir(s) 49,387,085,824 bytes free
C:\Documents and Settings\Knute Johnson\bigdirectory>java FileSystemsTest
0.txt
1.txt
10.txt
100.txt
1000.txt
10000.txt
10001.txt
10002.txt
10003.txt
10004.txt
16
C:\Documents and Settings\Knute Johnson\bigdirectory>
--
Knute Johnson
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The first 10 files Wojtek <nowhere@a.com> - 2013-01-26 01:14 -0800
Re: The first 10 files Roedy Green <see_website@mindprod.com.invalid> - 2013-01-26 02:44 -0800
Re: The first 10 files Lew <lewbloch@gmail.com> - 2013-01-26 10:20 -0800
Re: The first 10 files "John B. Matthews" <nospam@nospam.invalid> - 2013-01-26 06:31 -0500
Re: The first 10 files Wojtek <nowhere@a.com> - 2013-01-26 15:42 -0800
Re: The first 10 files Jim Janney <jjanney@shell.xmission.com> - 2013-01-26 17:13 -0700
Re: The first 10 files Arne Vajhøj <arne@vajhoej.dk> - 2013-01-26 21:21 -0500
Re: The first 10 files "John B. Matthews" <nospam@nospam.invalid> - 2013-01-26 22:05 -0500
Re: The first 10 files Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-01-26 08:24 -0400
Re: The first 10 files Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-01-26 08:25 -0400
Re: The first 10 files Arne Vajhøj <arne@vajhoej.dk> - 2013-01-26 13:26 -0500
Re: The first 10 files Robert Klemme <shortcutter@googlemail.com> - 2013-01-26 22:15 +0100
Re: The first 10 files Arne Vajhøj <arne@vajhoej.dk> - 2013-01-26 16:25 -0500
Re: The first 10 files Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-01-26 17:06 -0500
Re: The first 10 files Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-26 15:21 -0800
Re: The first 10 files Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-01-26 20:42 -0500
Re: The first 10 files Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2013-01-26 17:56 -0800
Re: The first 10 files Arne Vajhøj <arne@vajhoej.dk> - 2013-01-26 21:29 -0500
Re: The first 10 files Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-01-26 21:56 -0500
Re: The first 10 files Jim Janney <jjanney@shell.xmission.com> - 2013-01-26 20:51 -0700
Re: The first 10 files Jim Janney <jjanney@shell.xmission.com> - 2013-01-26 20:47 -0700
Re: The first 10 files Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-01-26 22:02 -0400
Re: The first 10 files Arne Vajhøj <arne@vajhoej.dk> - 2013-01-26 21:35 -0500
Re: The first 10 files Arne Vajhøj <arne@vajhoej.dk> - 2013-01-26 21:43 -0500
Re: The first 10 files Robert Klemme <shortcutter@googlemail.com> - 2013-01-27 13:55 +0100
Re: The first 10 files Arne Vajhøj <arne@vajhoej.dk> - 2013-02-24 17:50 -0500
Re: The first 10 files Robert Klemme <shortcutter@googlemail.com> - 2013-02-25 21:53 +0100
Re: The first 10 files Jim Janney <jjanney@shell.xmission.com> - 2013-01-26 20:57 -0700
Re: The first 10 files Wojtek <nowhere@a.com> - 2013-01-26 21:20 -0800
Re: The first 10 files Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-01-27 07:23 -0400
Re: The first 10 files Arne Vajhøj <arne@vajhoej.dk> - 2013-01-27 20:36 -0500
Re: The first 10 files Wojtek <nowhere@a.com> - 2013-01-28 16:28 -0800
Re: The first 10 files Arne Vajhøj <arne@vajhoej.dk> - 2013-01-26 21:23 -0500
Re: The first 10 files Roedy Green <see_website@mindprod.com.invalid> - 2013-01-26 19:09 -0800
Re: The first 10 files Jim Janney <jjanney@shell.xmission.com> - 2013-01-26 16:00 -0700
Re: The first 10 files Knute Johnson <nospam@knutejohnson.com> - 2013-01-26 18:37 -0800
Re: The first 10 files Wojtek <nowhere@a.com> - 2013-03-14 03:07 -0700
Re: The first 10 files lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-03-14 12:49 +0000
Re: The first 10 files Robert Klemme <shortcutter@googlemail.com> - 2013-03-15 11:38 +0100
Re: The first 10 files Wojtek <nowhere@a.com> - 2013-03-15 10:31 -0700
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