/
WriteBytesToFile.java
executable file
·68 lines (63 loc) · 2.36 KB
/
WriteBytesToFile.java
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/*
* #%L
* Netarchivesuite - common
* %%
* Copyright (C) 2005 - 2018 The Royal Danish Library,
* the National Library of France and the Austrian National Library.
* %%
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 2.1 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Lesser Public License for more details.
*
* You should have received a copy of the GNU General Lesser Public
* License along with this program. If not, see
* <http://www.gnu.org/licenses/lgpl-2.1.html>.
* #L%
*/
package dk.netarkivet.common.tools;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
/**
* A class with a method for creating large files. Bruce Eckel's solution
* (http://www.java2s.com/ExampleCode/File-Input-Output/Creatingaverylargefileusingmapping.htm) is slightly slower!
*/
public class WriteBytesToFile {
/**
* Writes a large number of bytes to a given file.
*
* @param args args[0] is the number of bytes to write args[1] the name of the output file
* @throws IOException If unable to write to output file
*/
public static void main(String[] args) throws IOException {
// A reasonably optimal value for the chunksize
int byteChunkSize = 10000000;
long nbytes = 0;
if (args.length != 2) {
System.out.println("Usage: java WriteBytesToFile nbytes filename");
System.exit(1);
}
try {
nbytes = Long.parseLong(args[0]);
} catch (Exception e) {
System.out.println("First argument must be a number");
}
File outputFile = new File(args[1]);
byte[] byteArr = new byte[byteChunkSize];
FileOutputStream os = new FileOutputStream(outputFile);
FileChannel chan = os.getChannel();
for (int i = 0; i < nbytes / byteChunkSize; i++) {
chan.write(ByteBuffer.wrap(byteArr));
}
os.close();
chan.close();
}
}