Mega Code Archive
0264 FileChannel
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A channel for reading, writing, mapping, and manipulating a file.
A file channel has a current position within its file which can be both queried and modified. File channels are safe for use by multiple concurrent threads.
FileChannel.MapMode.READ_ONLY defines a mode for a read-only mapping.
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
public class MainClass {
public static void main(String args[]) {
FileInputStream fIn;
FileOutputStream fOut;
FileChannel fIChan, fOChan;
long fSize;
MappedByteBuffer mBuf;
try {
fIn = new FileInputStream(args[0]);
fOut = new FileOutputStream(args[1]);
fIChan = fIn.getChannel();
fOChan = fOut.getChannel();
fSize = fIChan.size();
mBuf = fIChan.map(FileChannel.MapMode.READ_ONLY, 0, fSize);
fOChan.write(mBuf); // this copies the file
fIChan.close();
fIn.close();
fOChan.close();
fOut.close();
} catch (IOException exc) {
System.out.println(exc);
System.exit(1);
} catch (ArrayIndexOutOfBoundsException exc) {
System.out.println("Usage: Copy from to");
System.exit(1);
}
}
}
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